Refactor some logic from canvas and object classes into mixins
More canvas refactoring
Fix for dynamic_origin + Remove lines correctly on object moving

Fix if objects have different origins (originX != 'center' and/or originY != 'center')
Lines now removed correctly on object:moving (bug since commit c4bec7045532886a338ef7ae91c80bfd8fb28851)

[BACK_INCOMPAT] for fabric.js versions < 1.0.0
Merge pull request #391 from Kienz/patch-1

Fix for dynamic_origin + Remove lines correctly on object moving
Remove old yui compressor file
Update uglyfyjs, build distribution
merge with kangax