Add apiclient as an alias for googleapiclient.

We want to rename `apiclient` to `googleapiclient`; breaking everyone seems
like a **bad** way to do that. Instead, this keeps the old name as an alias.
diff --git a/apiclient/__init__.py b/apiclient/__init__.py
new file mode 100644
index 0000000..f84974b
--- /dev/null
+++ b/apiclient/__init__.py
@@ -0,0 +1,12 @@
+"""Retain apiclient as an alias for googleapiclient."""
+
+from googleapiclient import *
+
+from googleapiclient import channel
+from googleapiclient import discovery
+from googleapiclient import errors
+from googleapiclient import http
+from googleapiclient import mimeparse
+from googleapiclient import model
+from googleapiclient import sample_tools
+from googleapiclient import schema
diff --git a/setup.py b/setup.py
index 4ea3c76..d538246 100644
--- a/setup.py
+++ b/setup.py
@@ -29,6 +29,7 @@
 from setuptools import setup
 
 packages = [
+    'apiclient',
     'googleapiclient',
 ]