Merge pull request #2 from flainez/master

Fixed errors in the asserted variables.
Merge pull request #3 from flainez/master

Modify addCompactConstraints: to return an NSArray with the constraints created.
Do not rely on side effects in NSAssert calls
Merge pull request #6 from komola/master

Make CompactConstraint work in release builds
NSLayoutAttribute casts to fix strict warnings (fix #4)
Added "self" implicit view (fix #5)
Merge pull request #1 from marcoarment/master

Getting up to date with latest changes.