Clean commit with just my 1080p Hi DPI skins
added master and slave assets
Merge branch 'DJO_t-biggerskin' into master_sync

Conflicts:
	mixxx/res/skins/LateNight1280x800-4Deck-WXGA/skin.xml
fix problem with filebpm not getting initialized
added debug numbers to skin
qtcreator made these I think
Fix return type in TwoWayMessagePipe.
Check for NULL before TrackPointer deref.
Merging from lp:mixxx.
Brute-force importing of master_sync work done in github.
Fix a merge issue.
Be explicit about position in calls to getPhaseOffset.
Minor logic cleanup in BpmControl.
Remove redundant initialization of m_iSyncState.
Use control itself for looking up VC-enabled and sync-state.
Move rate-change sync logic out of EngineBuffer and into BpmControl.
Move beat-distance update logic out of EngineBuffer and into BpmControl. It's messier to keep track of the previous position in BpmControl but it keeps EngineBuffer cleaner.
Scaler can cap the rate so issue onEngineRateChange after setTempo.
Get rid of RateControl::m_pEngineMaster.
Fix the build.
Get rid of RateControl::getCurrentRate / m_dOldRate.