issue313: 1. create a subclass of UIAlertView with completion block 2. show an alert to confirm stopping an experiment
issue313: stop experiment, to be continued
Merge branch 'ios-init' of github.com:google/paco into issue313
issue313: the server needs an inputId for all events, which needs to be fixed later.
issue313: code refactoring of moving render join event to PacoEvent
Merge pull request #18 from google/issue17

issue17: disallow user to join an experiment multiple times
Merge branch 'ios-init' of github.com:google/paco into issue313

Conflicts:
	Paco-iOS/Paco/source/core/client/PacoClient.h
Merge branch 'issue313' of github.com:google/paco into issue313
Merge pull request #15 from google/issue313

Issue313-GoogleCode