HTML5: splitting the css files in several sections

So we can work on them in paralell to implement the new layout.
HTML5: showing/hiding elements when navbar buttons are clicked
Users list style updates
HTML5: impemeting the layout positioning for mobile devices
Public chat style updates
HTML: layout with fullsize components when in very small screens

For mobile phones on portrait mode, chat, user list and video are shown
taking the whole screen.
HTML5: remove all old css files and adjust what's left
Merge pull request #293 from daronco/html5-bridge-new-layout

HTML5 new layout, first version