Merge pull request #4 from mobilejazz/master

Update from mobilejazz:master
Merge branch 'development' of github.com:mobilejazz/Motis into NSDate
New Podspec for version 0.4.2
Nil date formatter by default + validate string with timestamps as dates
Merge pull request #10 from robotmedia/NSDate

Nil date formatter by default + validate string with timestamps as dates
Changing date formatter behaviour
Improving tests