Gulp optimizations to combine and minify js/css files.

Incorporated changes references by @crackcomm https://github.com/crackcomm/Responsive-Dashboard/commit/91fc2c8bc328981f9722bb4c7e97042b3ac03440 on #48.

 * Combines and minifies all 3rd party libraries into vendors.min.js
 * Combines and minifies all dashboard js files
 * Incorporates angular template cache and moves dashboard.html and tables.html into templates sub-directory.
 * Compiles less, combines with 3rd party libs and minifies into dashboard.min.css.