Added utility description, epilog and switched to relative imports
Added Channel.stop API that takes care of channels registry too
Returning appropriate error codes (typo fixed), catching invalid DSN exception
Updated channel communication protocol to return a dictionary instead of stdout or stderr stream. Returned dict contains following attributes:

a) stdout
b) stderr
c) exit_code

REST API returns a json form of this python dict
close stdin (not required)
Refactor and tests for RESTful API
Added REST API detail inside README
Added doc for SSH channel meta info dict and command response dict inside README
exec_command wrapper refactoring to return stdout, stderr, exit_code
Returning internal server errors during command execution as 'exception' attribute of command response dictionary
Info message for instance when channel has been detected dead and restarted
Merge pull request #2 from abhinavsingh/develop

Refactoring, protocol update, tests, documentation