Messaging data model changes and bug fixes.

Messaging data model changes and bug fixes (controllers).

Refactoring and fixes.

Refactoring of S3ChannelModel - enable/disable/schedule controllers. Bug-fixing.

Fixes.

Fix to allow same username with multiple servers.

Final Fixes to Messaging Channel data model.

Pep-8 styling, fixes.

Comments.

More pep8.
Merge pull request #521 from ashwyn/master

Messaging data model changes and bug fixes.