Merge pull request #64 from reaperhulk/travis-test-cryptography-master

Test against cryptography's master branch
diff --git a/.travis.yml b/.travis.yml
index 68149b4..52f1032 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -11,6 +11,24 @@
   - "3.2"
   - "3.3"
 
+matrix:
+  include:
+  - python: "2.6"
+    env: CRYPTOGRAPHY_GIT_MASTER=true
+  - python: "2.7"
+    env: CRYPTOGRAPHY_GIT_MASTER=true
+  - python: "3.2"
+    env: CRYPTOGRAPHY_GIT_MASTER=true
+  - python: "3.3"
+    env: CRYPTOGRAPHY_GIT_MASTER=true
+  - python: "pypy"
+    env: CRYPTOGRAPHY_GIT_MASTER=true
+  allow_failures:
+  - env: CRYPTOGRAPHY_GIT_MASTER=true
+
+before_install:
+  - if [ -n "$CRYPTOGRAPHY_GIT_MASTER" ]; then pip install git+https://github.com/pyca/cryptography.git;fi
+
 install:
   # Install the wheel library explicitly here.  It is not really a setup
   # dependency.  It is not an install dependency.  It is only a dependency for