Adds favicons to top site listing.

Improves the new tab UI design to be more touch friendly.
Adds new wallpaper scaling options: 'none' and 'automatic'.
Adds the option to show/hide top sites.

Adds a wallpaper preview box to the options page.
Adds a new wallpaper scaling option: 'fill'.
Adds support for dynamic plain-text wallpaper URL lists.
Allow wallpaper imports from Imgur galleries (in addition to albums).
Adds feedback for context menu actions through notifications.

Fixes a bug where particularly wide wallpapers were not fully contained in a new tab's frame.

Simplifies wallpaper list UI in the options page.
Allows download of the wallpaper URL list as a text file.
Adds a dark theme to the options page (under the advanced category).
Fixes a bug where the specified duration for the animation of the background/wallpaper would not be saved correctly (sometimes).

Fixes a bug where the image context menu was enabled even when the display of wallpapers was disabled.