samgreen/CGVector-Awesome — pull request #1 by vigorouscoding (2014-06-05 22:03:36+00:00)
Title: CGVectorAngleBetween fix 

CGVectorAngleBetween should use ```acos``` to calculate the angle.

I also added some tests to ensure that this is the correct behavior. Unluckily the old test ran successfully even though the function didn't behave correctly.

That being said: Thank you for these cool CGVector additions!