Manager interface
Basic (incomplete) implementation.
Still needs a few major DAO changes
Tests for existing implementation.
Since the manager was implemented before the major DAO changes, some revisions are required.
Test requires fewer revisions since the interface changed (much) less than the implementation
Code review changes from DAO level
Revise manager to use new DAO and design
Oops, somehow forgot to add a test for getConversation(...)
Finish up test revision
Merge pull request #824 from kaysoky/MessageManager

Messaging - Manager level

Great job!!