Some of the operators in the geometry additions have unclear behavior

[NickEntin]

Specifically, we should convert the following operator overloads into methods to improve clarity around what their function is and what type they will return:

• -(CGPoint, CGPoint) should be converted to CGPoint.offset(to:)
• +(CGPoint, UIOffset) should be converted to CGPoint.offset(by:)
• +(CGRect, UIOffset) should be converted to CGRect.offset(by:)

[NickEntin]

-(CGPoint, CGPoint) would actually be directly converted to CGPoint.offset(from:), but I think CGPoint.offset(to:) reads better. We could also potentially have both versions available.