test branch
offline library events manipulation
offline library ...
filtering events using predicate
offline library events and filtering
sync problems fixed
channels caching, events
channels management, events offline management, synching
offline folders and events (folders not fully tested)
attachments support for sync
test cases prepared initial
caching test ...
tests
a few more tests...
project changes
removed some not needed files
cleaning code
sdk docs
crash fix
Merge branch 'offline-library' of https://github.com/pryv/sdk-objectivec-apple

Conflicts:
	PryvApiKit.xcodeproj/project.pbxproj
	PryvApiKit/PYAccess.m
	PryvApiKit/PYCachingController.m
	PryvApiKit/PYChannel.h
	PryvApiKit/PYChannel.m
	PryvApiKit/PYConstants.h
	PryvApiKit/PYConstants.m
	iOs Example/PYEViewController.m