begin development of v0.5 (#94)

Author: Russell Hay

setup.py

@@ -5,7 +5,7 @@
 
 setup(
     name='tableaudocumentapi',
-    version='0.4',
+    version='0.5.dev0',
     author='Tableau',
     author_email='[email protected]',
     url='https://github.com/tableau/document-api-python',