Added nil check for object validation.
Merge pull request #32 from jcgsxr/fix/nsnull

Added nil check for object validation.
Remove synthesize directives.
Merge pull request #33 from jcgsxr/feature/cleanup_synthesize

Remove synthesize directives.
version bump to 0.1.3
Expose participatingUsers getter and setter methods.
Merge pull request #34 from jcgsxr/fix/expose_conversation_methods

Expose participatingUsers getter and setter methods.
Update README to reference 0.1.3
Type def for failure response block. Add parameter name to methods for better auto-complete.
Added message sending API
Added send message unit test.
Update sendMessage failure callback to use typedef block.
Merge pull request #35 from jcgsxr/feature/messages

Feature/messages