* create VinylMode pushbutton correctly
* don't need these qdebugs anymore (merge features_xwax2 2471)y
* merge from trunk (fix conflicts)
* merge with trunk
* we don't need to worry about device problems here (I think?)
* merge from trunk (crashes)
* fix startup crash. Don't try to initialize cotnrolobject values right after creating the threads (merge from features_xwax2 2477)
* fix pushbuttons to work with multistate pushbutton widgets
* fix pushbuttons so that toggles work with midi controllers that do toggling (nanokontrol)
* fix vinyl code so that it's not specific to my nanokontrol setup
* simplify mode-switching code: don't allow switch to ABS mode if playing and needleskip prevention is on
* merge from trunk
* add hack to skin loader to load custom skins for fullscreen code
* merge from lp:~mixxxdevelopers/mixxx/features_flac
* merge from lp:~mixxxdevelopers/mixxx/features_library
* restore library prefix hack
* merge from lp:mixxx
* fix vinyl control checkboxes not working
* merge from lp:mixxx
* merge from lp:~ywwg/mixxx/features_xwax2:
  * adapted to new pref dialog design
  * adapted vinyl code to work with new n-deck design.
* merge back with lp:mixxx, ugh.
* merge from lp:~ywwg/mixxx/features_xwax2 -c 2486:
  * redo vinyl input mapping to support arbitrary numbers of decks
  * to enable "single deck mode" set both decks to the same set of inputs
* fix constant mode playback speed