CSS/JS/LESS/File Upload update

Updated LESS/CSS with latest bootstrap files, added submenus (deleted in 3.0), added .polaroid classes in css, other CSS changes.
Added some unminified CSS and JS files
Added support for additionnal libs in controllers
Added simpleImage library to do basic image manipulation
Added better (uh, what was my last commit ?) file upload support in add() actions
Added empty dirs for uploads