[Mobile] Reorganize

Reorganized the sass files. To incorporate, new
mobile directory, which holds all the mobile
sass code.

platform/commonUI/general/res/sass/_main.scss

@@ -27,10 +27,14 @@
 @import "compass/utilities";
 
 @import "mixins";
+@import "mobile/mixins";
+
 @import "effects";
 @import "global";
 @import "fonts";
 @import "user-environ/layout";
+@import "mobile/layout";
+
 @import "fixed-position";
 @import "about";
 @import "text";