HttpOAuth2Connector refactoring
  - Improved error handling - how returns error data in a JSON body
  - Use private method to copy response data over to the real response
  - Do not auto-create sessions when retrieving current session
Initial refactoring of Share OAuth into separate repo and Share modules
  - Share and repo code and config separated into sub-modules
  - Top-level pom only builds Share module for now
Add repo-tier pom
Add OAuth 2.0 token web scripts copied from Chatter add-on
Refactor webscripts used to get and set OAuth tokens
  - Move into org.sharextras package
  - Add web scripts Spring config and descriptors from Chatter project
Update README to reflect new submodule structure