add KVO dependent key and key path tests. remove -testMidCycleReregisterPartialWithContext as it seems to put KVO in a very bad state.

remove commented-out method pending verification on iOS device. Currently, it crashes on the *next* use of KVO making it particularly hard to track down.
Merge branch 'master' of github.com:apportable/FoundationTests

Conflicts:
	src/NSKVOTests.m