Migrate AutoLayout Helpers

Pulls the Autolayout helpers submitted in https://github.com/domesticcatsoftware/DCIntrospect/pull/60
Adds method to colour ambiguous layouts

Adds UIView category that allows us to non destructive colouring of views
Selected views with ambiguous layouts now show a red exclamation next to the frame
Merge pull request #13 from tapi/AutoLayout-Helpers

Auto layout helpers