- fix up composing status / call system messages to be a structure instead of an interface
https://github.com/openpeer/opios-production/issues/167
Merge remote-tracking branch 'origin/feature-20140730-is-composing' into feature-20140521-push-messaging

Conflicts:
	projects/xcode/hfcore_ios/hfcore_ios.xcodeproj/project.pbxproj