Change the docs to not require library installation

docs/conf.py

@@ -48,18 +48,22 @@ copyright = u'2013, Author'
 # built documents.
 #
 # The short X.Y version.
-import pkg_resources
-try:
-    release = pkg_resources.get_distribution('capnp').version
-except pkg_resources.DistributionNotFound:
-    print 'To build the documentation, The distribution information of sandman'
-    print 'Has to be available.  Either install the package into your'
-    print 'development environment or run "setup.py develop" to setup the'
-    print 'metadata.  A virtualenv is recommended!'
-    sys.exit(1)
-del pkg_resources
+def extract_version():
+    """extract version from version.py, so it's not multiply defined"""
+    with open(os.path.join('..', 'capnp', 'version.py')) as f:
+        line = f.readline()
+        while not line.startswith("version"):
+            line = f.readline()
+            print line
+    exec(line)
+    return version
 
-version = '.'.join(release.split('.')[:2])
+vs = extract_version()
+# The short X.Y version.
+import string
+version = vs.rstrip(string.letters)
+# The full version, including alpha/beta/rc tags.
+release = vs
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.