merge for v1.8 - implement QBrowser layer

[raphaelquast]

activate with shift + recall

• QBrowser uses info-messages instead of the browser-window to display selections! (the browser-window it is inaccessible via MidiRemoteScripts)
• fully compatible with Ableton 10 & 11

Browser control features

• [x] navigate folder-structure
  • button 9 : left
  • button 10: go 1 folder up
  • button 11: go 1 folder down
  • button 12: right
  • transpose-encoder: scroll
  • [x] quick access to parent folders
  • use button 1-6 to access top-level folders: [Sounds, Drums, Instruments, Audio-Effects, Midi-Effects, Samples, Collections]
• [x] load selected item
  • tap button 15 to load the selected item
  • [x] use shift + button 15 to create new track & load the device there
    • instruments are loaded to midi tracks
    • clips and samples are loaded to audio-tracks
    • effects are loaded to return-tracks
• [x] prelisten items
  • use button 14 to toggle pre-listening selected items (blue light indicates prelisten is ON)
• [x] hotswap items
  • [x] basic hotswap functionality implemented
  • use button 13 to toggle hotswapping the currently selected device

secondary features

• buttons
  • [x] use button-features of control-layer if shift is pressed
• encoders
  • [x] use all encoder-features of control-layer
  • [x] use shift + button 8 and shift + button 16 to select devices

TODO's:

• [ ] handle grooves
• [ ] handle templates
• [ ] handle plugins
• [ ] handle places (e.g. user-library, packs, current_project, ...)
  • how to identify item-type of general object? (right now parent-folders are used for identification)
• check _find_item() and find_device() for possible performance-issues