Bug 830644 - Support WVGA and other non-HiDPI screen dimensions and resolutions
    - Lockscreen: converted px to rem, linked resposnive.css from system and some js tewaks for wallpaper canvas
    - Added lockscreen @2x assets
Merge pull request #8297 from basiclines/responsive-ui

Bug 830644 - Support WVGA and other non-HiDPI screen dimensions and resolutions