[Frontend] Further cleanups to form elements

#700
#689
#740
Removed _selects.scss and moved classes
into _controls.scss;
Reorg'd _controls;
Moved classes into _elems.scss;
Added and fixed cssclass defs in multiple
bundle.js files to allow better field widths
in overlay dialogs;
Fixed overlay custom scrollbar colors;
Fixed alignment of required glyphs in forms;

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

@@ -45,7 +45,6 @@
 
 /********************************* FORMS */
 @import "forms/elems";
-@import "forms/selects";
 @import "forms/channel-selector";
 @import "forms/datetime";
 @import "forms/validation";