Added define option to uglifyjs2 filter - Added unit tests & fixed uglifyjs tests.
Now accepting multiple define options - Added define option to uglifyjs too (ping @pjordaan).
removing dead code / commented line.
Reverting uglifyjs bin name.
Merge pull request #525 from shouze/feature/uglifyJS2/AddDefineOption

Added define option to uglifyjs (1 & 2) filters w/unit tests