Fix comment typo
HttpOAuth2Connector now working with OAuth2Authenticator to load up
tokens from the persistent credential store. Still need to fix NPE when
retrieving Alfresco connector.
Initial working snapshot of OAuth2Connector
  - OAuth2Authenticater is no longer used, as we cannot get the session
and user context required to get hold of the Alfresco connector
  - OAuth2 return webscript now uses endpointId property (configured via
Spring) to scope the storage of tokens
  - Updated path of get and set token webscripts, which can be
overridden in subclasses in getTokenApi() method
  - Get and set token URL webscripts now use URL tokens rather than
parameters
  - Removed the annoying credentials_ prefix previously added by the
vault
Initial implementation of HttpOAuth2QueryStringConnector
  - Allows access to OAuth2-protected resources using a querystring
parameter
Send Accept: header when requesting access token to ensure a JSON
response comes back (required for GitHub)
 - Also improved debug logging
Re-load credentials from the repository when a 403 response is received
from the upstream provider
Build against 4.2.d release
OAuth 2.0 return web script improvements
  - Web script can be used directly, no need to declare a new bean
  - Endpoint ID taken from web script path token
  - All other parameters are looked up from the connector descriptor
Allow OAuth 2.0 parameters to be declared in the endpoint descriptor
instead of the connector
  - Avoids the need to declare new connectors in each project
  - Parameters are accessible via the 'remote' root context object in
JavaScript, allowing client IDs to be injected into page components.
Declare a generic HttpOAuth2QueryStringConnector connector which can be
used by client projects
OAuth 2.0 connector fixes
  - Retrying requests after an initial 401/403 response now works
  - Application context is now always set correctly on the connector
instance
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