* [Web-API/Contexts] Implemented 'GET /rest/contexts/list.json' in the Web-API for retrieving a list of context IDs and names.  The context IDs are used for making various kinds of requests (e.g. attachment links, comments, record links) and there wasn't a comprehensive list available anywhere.  This API request will also include any contexts that were added through plugins, which the standard documentation wouldn't include.
[Code Cleanup/Contexts/Links] Improved the DAO_ContextLink ::setLink and ::deleteLink calls so they can reuse context meta if it was already looked up.  This prevents double lookups.  For instance, the Web-API can load contexts to verify access before asking for links to be created.
[Code Cleanup]
* [CHD-3562] [Web-API/Contexts/Links] Implemented 'POST /rest/contexts/link.json' in the Web-API for adding any number of links to a record. See: http://cerbweb.com/book/latest/developer_guide/rest_api/contexts.html

* [CHD-3562] [Web-API/Contexts/Links] Implemented 'POST /rest/contexts/unlink.json' in the Web-API for removing any number of links from a record. See: http://cerbweb.com/book/latest/developer_guide/rest_api/contexts.html
6.6-rc checkpoint