crude initial adwaita > HC port
doap category core
HC: flat OSD
HC: fix borders
HC: contrasty buttons
HC: sync dualogs with Adwaita
HC: thick button strokes
HC: selectable list items (sync with Adwaita)
HC: checkboxes and radios
Merge branch 'wip/hc-sass'

- Share style elements with Adwaita
- Keep similar structure as Adwaita
HC: provide hover state for checkboxes

- not very clear due to :active/:selected vs :checked

https://bugzilla.gnome.org/show_bug.cgi?id=732486
HC: fix backdrop colors
HC: colored suggested buttons

https://bugzilla.gnome.org/show_bug.cgi?id=732493
HC: use symbolic icons rather than a specific theme

https://bugzilla.gnome.org/show_bug.cgi?id=732521
HC: use symbolic icons for HC

- drop the custom rendered theme in favor of recolorable
  symbolic icons from Adwaita

https://bugzilla.gnome.org/show_bug.cgi?id=732521
background: move from here to gnome-backgrounds

- default bg now ships with gnome-backgrounds instead
  where the lock screen was.
Revert "HC: use symbolic icons for HC"

Pushed this prematurely by accident.
Revert "HC: use symbolic icons rather than a specific theme"

Revert gtk part of the HC>symbolic move. Pushed prematurely :(