Add binderFromObject:keyPath:toObject:keyPath:formatter: method to create a binder that uses a NSFormatter (like NSDateFormatter or NSNumberFormatter)
Merge pull request #7 from 5sw/master

Binder with NSFormatter
New self-observation test.
Merge remote-tracking branch 'github/master'

Conflicts:
	THObserversAndBindersTests/THObserversAndBindersTests.m
Merge branch 'master' of https://github.com/th-in-gs/THObserversAndBinders