Merge lp://qastaging/~mixxxdevelopers/mixxx/features_trackbeats into lp://qastaging/~mixxxdevelopers/mixxx/trunk

Adding a method to TrackBeats for ascertaining if a sample range has a beat. Wishlist #699971.

Minor fixes to TrackBeats: pass samples/seconds QLists by reference and fix the parameter names for hasBeatsSamples.

FIX: get waveformrenderbeat to use the samples QList from TrackBeats by reference.

FIX: get TrackBeatsPointer to correctly work and have it be freed automatically, just as it should.

FIX: change setTrackBeats call in AnalyserBPM.

Cleaning up the order of TrackBeats and creating the few remaining Seconds equivalent functions.

Commenting of functions and addition of the last seconds equivalent functions. Also adding removeBeatSample function and it's seconds equivalent.

Removing unecessary white space.

Tweaks to adding and removing samples.

Add Beats abstract interface with a BeatGrid implementation.

Tighten up the Beats/BeatGrid interface a little bit. Add a reimplementation of TrackBeats as BeatMatrix

Remove TrackBeats. Change TIO, Analyser, and Waveform to use Beats generic interface instead. Add versioned serialization to TrackDAO. Move creation/destruction of the Beats variants into a BeatFactory class. Most awesome class name, ever.

Fix lack of deletion of RenderObjects in WaveformRenderer

Add destructor traces for TIO. Delete the WaveformRenderer.

Tracks are no longer being deleted. Turning on deletion print in TrackDAO. Clear the track cache when TrackDAO is destroyed.

Fix SQL statement that got munged by a merge.

Rephrase :wavesummaryhex binding to match :beats

Doh. Forgot to add BeatFactory files

FIX: error in ternary syntax.

FIX: generate BeatGrid if we do not have a beatgrid but we have detected the BPM of the song already.

Various changes will bring the new Beats classes into feature parity with the
old trackbeats code.

  * beatfactory.cpp: include beatgrid.h and beatmatrix.h because forward
                     declaration proved to not be enough.
  * beats.h, beatgrid.h, beatmatrix.h: adding findNthBeat method.
  * beatgrid.cpp: many changes and fixes, including adding findNthBeat.
      - implement findNthBeat. calculate the beat using m_dFirstBeat.
      - reimplement findPrevBeat and findNextBeat using findNthBeat.
      - replace all other beat calculations with calls to findNextBeat.
  * beatmatrix.cpp:
      - implement findNthBeat.
      - reimplement findPrevBeat and findNextBeat using findNthBeat.

Add language to beats.h that makes clear the behavior of findNextBeat and findPrevBeat when dSamples refers to the location of a beat.

BeatMatrix::findNthBeat fixes for going in the negative direction. Changed variable from offset to n and updated comments to reflect that.

Fixup BeatGrid::findNextBeat a little bit. It wasn't doing the previous direction correctly.

Add some parameter checks to BeatGrid.

Move BeatGrid legacy check from AnalyserBpm to TrackDAO so that any track loaded from DB will get a BeatGrid if it does not have one already and already has a BPM (or if the file metadata has a stored BPM)

Merging from trunk.

Move beat-related classes to track/

Merging from Repository.

Use a struct for (de)serializing the beat, for beatgrid, from the database.

Undo application of SSE3 patch (not the time nor the place for it).

Make the QByteArray argument to readByteArray and both Beat classes a const.

Rename struct to BeatGridData and fixed QByteArray pointer leak in TrackDAO.

Merge from trunk

Merge from trunk

FIX: change track beats code to use sample offsets instead of frame offsets. this way the code fits in with the rest of the codebase.

Comments for beatgrid units, contributed by Albert Santoni.

Change beatgrid to serialize in frame offsets but use sample offsets at runtime.

Cleaning up some cruft left over from earlier shift to using sample offsets at runtime.