For some reason the exported bitmaps in #2211 were not properly saved in the right
format for display by the NSIS installer system.
Signed-off-by: Michael Schuster <michael@schuster.ms>
This implements out-of-repository-theming, and removes the old
custom.ini theming that never worked on all platforms and had
no straight deployment story.
The new approach requires the CMAKE variable OEM_THEME_DIR to
point to a directory that must at least contain an OEM.cmake file
(check OWNCLOUD.cmake for possible options) as well as a themes.qrc
and a themes/ directory that directly correspond to the ones in
the source tree.
