MomentsJS columns

This pull request is to implement #126, #123 and #79.

It makes more use of MomentJS to compute columns.

Demo available : http://rawgit.com/angular-gantt/angular-gantt/momentjs-columns/demo/dist/index.html

TODO:

- [x] Quarter and year column
- [x] Calendar factory to configure TimeFrames and DateFrames
- [x] TimeFrame conflict solver
- [x] Drawing of TimeFrames
- [x] Option to enable/disable drawing of timeFrames (working and non-working)
- [x] Implement cropped option for TimeFrames to perform like before
- [x] Column Magnet
- [x] Performance optimization of Column factory in cropped mode