Add breakpoints management librairies

Add grunt-contrib-compass (required)
Edit gruntfile.js (add compass tasks)

--don't forget to update bower components

UI/WebServerResources/scss/styles.scss

@@ -7,11 +7,14 @@
 *
 **/
 
-@import 'core/variables'; // Will be replace by a complete 'config file
-
-// Compass import - comment-out if needed
+// Compass extension imports - comment-out if needed
 // ------------------------------------------------------------------------------
-@import '../bower_components/compass-mixins/lib/_compass';
+@import '_breakpoint-slicer.sass';
+@import '_breakpoint.scss', '_sassy-maps.scss';
+// This is no longer required because we use grunt-contrib-compass (ruby required)
+//@import '_compass.scss';
+
+@import 'core/variables'; // Will be replace by a complete 'config file
 
 // Browser reset - most effective for applications. Generated by Compass in a non-regular way
 // ------------------------------------------------------------------------------