diff widgets/Fader.h @ 33:651e4e868bcc

* Implement play mute, level and pan controls and a layer visibility control
* Handle swapping the buffers in AudioCallbackPlaySource more gracefully, so
  that in many cases it can be done inaudibly.  Still gets it wrong when
  playing in a noncontiguous selection.
* Fix to SV file save for non-2d sparse models
* Fixes to LED button drawing and AudioDial mouse functionality
* Add progress bar for Ogg file import
* Reshuffle PropertyContainer and its subclasses so it can be a QObject
* Add layer dormancy (invisible layer permitted to free its cache space)
* Optimisations to SpectrogramLayer, removing locks when reading/writing
  individual pixels in the cache (should be unnecessary there) -- there's
  still an issue here as we need a lock when reading from the model in
  case the model is replaced, and we don't currently have one
* Several munlock() calls to make it harder to exhaust real memory if
  running in an RT mode with mlockall() active