[Mobile] Reorganize

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

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

@@ -26,5 +26,8 @@
 @import "compass/utilities";
 
 @import "constants";
+@import "mobile/constants";
 @import "mixins";
-@import "items/item";
+@import "mobile/mixins";
+@import "items/item";
+@import "mobile/item";