Don't run concat on JS.
It creates an unnecessary concatenated file that gets commited and makes reviewing pull requests hard.
Remove obsolete file.
Remove references to main.js since it has been removed.
Updates Uglify task.
* Adds beautify option set to false so we can quickly change back and forth.
* Adds and compiles sourcemaps.
Merge pull request #26 from himedlooff/clean-grunt

Remove main.js