* move color-regions-using-track color into UI config, not RC config
* consolidate all waveform coloring into AudioRegionView::set_one_waveform_color()
Mostly this just involved removing the private CacheEntry class that really served no further purpose once
the design reverted to a single cached image
note: the solution is non-obvious, but the obvious one of applying a translational Cairo::Matrix to the gradient
caused an exception to be thrown because of a non-invertible matrix.
Make download of sound files multi-threaded. Each sound file download takes
place in its own thread, and has its own progress bar and cancel button,
which stack up from the bottom of the list of results.
Sound files download into a file with a '.part' suffix, which is then
renamed to the intended name on success.
Add a 'Similar' button, which searches Freesound for sounds similar to the
currently-selected sound in the results list.
Add a freesound-download-dir config variable to decide the location
of sound files downloaded from Freesound.
Move Windows-specific logic to replace '/'s with '\'s from
Mootcher::changeWorkingDir() to Mootcher::ensureWorkingDir(), and remove
the now unused Mootcher::changeWorkingDir().
Use Glib::build_filename to construct paths.
Add constants for the keyboard modifiers that should be used for vertical
zoom, horizontal zoom, and horizontal scrolling in the main editor window,
and use these where appropriate rather than using Keyboard::PrimaryModifier
and friends directly.
Rather than maintain a set of images in a cache, when we no longer have the required waveform data, create a new image that is appropriately centered and extends to roughly twice the screen width (or the limits of the region's source file(s), as necessary)
Replace AU_STATE_SUPPORT compile-time define with NO_PLUGIN_STATE and make it prevent plugin state setting, preset loading, preset saving and plugin state saving. Blocks on these actions exist partially in the backend and partially in the GUI (this latter class are not absolute, and should OSC or MIDI be able to drive Plugin::save_preset() the block could be circumvented). Set NO_PLUGIN_STATE if --freebie is used at waf-configure time
