Custom location can now be set for weather bar.
Added small tips on location setting.
Reset data if there is no address.
Don't show both if city and country are the same.

Example, Singapore.
24 hour time can be configured now.
Flatten nav gradient a lot to fit the theme.
Enable offline in manifest.
Added a topsites bar. Pretty working.
Fixed expanded view of topsites.
Added reorder buttons to datetime bar.
Added move functions, yet to be implemented.
Show reorder buttons only when editing.
Fix gaps in bar's buttons.
Store an id along with bars.

Previously we were using the $index of each bar, but this can change in the
presence of the reordering feature. So, we need a more persistent id attribute.
Move down implemented.
Move up implemented.
Hide move buttons on first and last items.

Move down button last item and move up button on first are item are of no use
(unless we have wrapping that is). So, they are hidden.
Move all left buttons to a directive+template.
Read bar icons from the registry.
Reordering buttons present on all bars now.