Merge pull request #8 from bakercp/master

Conform to ofxAddonsTemplate + Modernization.
Added copy constructor to ofxTween and clone method to ofxEasing for more diversely applicable handling of ofxTweens dynamic allocations
Realised that the clone method for ofxEasing was unnecessary and removed it
Added copy assignment operator to complete the Rule of Three
Fixed missing return in assignment operator
Merge pull request #10 from mitchmindtree/master

Added copy constructor to ofxTween to handle ofxTween's dynamic allocations during copy.