Bug 870739 - Polishing multi-resolution support

* Progress bars issues resolved
* Extra space at bottom dialer tab removed
* Video app scaling issues fixed
* Missing bluetooth phone/pda icon fixed
* Network activity icons now scale up correctly
* Lockscreen unlock icon re-do (it was bigger than normal)
* Re-ordered responsive.css file to avoid having impact in application first paint (i'll not ping app authors as is a minor change)
*  style_unstable/scrolling.css now supports different devices ratio
* Contacts scrolling @2x icons fix
* Added missed @2x assets


I think i will need review from app owners because of important fixes in their modules: @borjasalguero @timdream @rexboy7  @gtorodelvalle @davidflanagan