build.yaml centric versioning
diff --git a/tools/buildgen/build-cleaner.py b/tools/buildgen/build-cleaner.py
index 37fedec..49a3644 100755
--- a/tools/buildgen/build-cleaner.py
+++ b/tools/buildgen/build-cleaner.py
@@ -38,7 +38,6 @@
 TEST = (os.environ.get('TEST', 'false') == 'true')
 
 _TOP_LEVEL_KEYS = ['settings', 'proto_deps', 'filegroups', 'libs', 'targets', 'vspackages']
-_VERSION_KEYS = ['major', 'minor', 'micro', 'build']
 _ELEM_KEYS = [
     'name',
     'cpu_cost',
@@ -83,8 +82,6 @@
   with open(filename) as f:
     js = yaml.load(f)
   js = rebuild_as_ordered_dict(js, _TOP_LEVEL_KEYS)
-  js['settings']['version'] = rebuild_as_ordered_dict(
-      js['settings']['version'], _VERSION_KEYS)
   for grp in ['filegroups', 'libs', 'targets']:
     if grp not in js: continue
     js[grp] = sorted([clean_elem(x) for x in js[grp]],
diff --git a/tools/buildgen/plugins/expand_version.py b/tools/buildgen/plugins/expand_version.py
new file mode 100755
index 0000000..9f9c7c7
--- /dev/null
+++ b/tools/buildgen/plugins/expand_version.py
@@ -0,0 +1,94 @@
+# Copyright 2015, Google Inc.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions are
+# met:
+#
+#     * Redistributions of source code must retain the above copyright
+# notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+# copyright notice, this list of conditions and the following disclaimer
+# in the documentation and/or other materials provided with the
+# distribution.
+#     * Neither the name of Google Inc. nor the names of its
+# contributors may be used to endorse or promote products derived from
+# this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+"""Buildgen .proto files list plugin.
+
+This parses the list of targets from the yaml build file, and creates
+a list called "protos" that contains all of the proto file names.
+
+"""
+
+
+import re
+
+LANGUAGES = [
+  'core', 
+  'cpp', 
+  'csharp', 
+  'node', 
+  'objc', 
+  'php',
+  'python', 
+  'ruby', 
+  ]
+
+class Version:
+
+  def __init__(self, s):
+    if '-' in s:
+      s, self.tag = s.split('-')
+    self.major, self.minor, self.patch = [int(x) for x in s.split('.')]
+
+  def __str__(self):
+    """Version string in a somewhat idiomatic style for most languages"""
+    s = '%d.%d.%d' % (self.major, self.minor, self.patch)
+    if self.tag:
+      s += '-%s' % self.tag
+    return s
+
+  def pep440(self):
+    """Version string in Python PEP440 style"""
+    s = '%d.%d.%d' % (self.major, self.minor, self.patch)
+    if self.tag:
+      # we need to translate from grpc version tags to pep440 version
+      # tags; this code is likely to be a little ad-hoc
+      if self.tag == 'dev':
+        s += '.dev0'
+      elif len(self.tag) >= 3 and self.tag[0:3] == 'pre':
+        s += 'rc%d' % int(self.tag[3:])
+      else:
+        raise Exception('Don\'t know how to translate version tag "%s" to pep440' % self.tag)
+    return s
+
+def mako_plugin(dictionary):
+  """Expand version numbers:
+     - for each language, ensure there's a language_version tag in
+       settings (defaulting to the master version tag)
+     - expand version strings to major, minor, patch, and tag
+  """
+
+  settings = dictionary['settings']
+  master_version = Version(settings['version'])
+  settings['version'] = master_version
+  for language in LANGUAGES:
+    version_tag = '%s_version' % language
+    if version_tag in settings:
+      settings[version_tag] = Version(settings[version_tag])
+    else:
+      settings[version_tag] = master_version
diff --git a/tools/doxygen/Doxyfile.c++ b/tools/doxygen/Doxyfile.c++
index cdb998d..5bc38a9 100644
--- a/tools/doxygen/Doxyfile.c++
+++ b/tools/doxygen/Doxyfile.c++
@@ -40,7 +40,7 @@
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/tools/doxygen/Doxyfile.c++.internal b/tools/doxygen/Doxyfile.c++.internal
index 558ec9d..ec71d2e 100644
--- a/tools/doxygen/Doxyfile.c++.internal
+++ b/tools/doxygen/Doxyfile.c++.internal
@@ -40,7 +40,7 @@
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/tools/doxygen/Doxyfile.core b/tools/doxygen/Doxyfile.core
index a3b4581..0f22620 100644
--- a/tools/doxygen/Doxyfile.core
+++ b/tools/doxygen/Doxyfile.core
@@ -40,7 +40,7 @@
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a
diff --git a/tools/doxygen/Doxyfile.core.internal b/tools/doxygen/Doxyfile.core.internal
index e91b47c..a354077 100644
--- a/tools/doxygen/Doxyfile.core.internal
+++ b/tools/doxygen/Doxyfile.core.internal
@@ -40,7 +40,7 @@
 # could be handy for archiving the generated documentation or if some version
 # control system is used.
 
-PROJECT_NUMBER         = 0.13.0.0
+PROJECT_NUMBER         = 0.13.0-dev
 
 # Using the PROJECT_BRIEF tag one can provide an optional one line description
 # for a project that appears at the top of each page and should give viewer a