Add Audio Editor - Instruments

[RobDavenport]

First Pass at Audio Editor. It's a big one, but these are all of the required steps for the audio being "proof of concept complete" for now. There are some other features which would be "nice to haves" but I'm going to leave that for a later point.

Bonus Ninja Changes:

• [X] Added Noise Waveform
• [X] Interpolator settings (linear, trunc, round)
• [X] Improve rollback flow on audio callback
• [x] Add LoopMode for sample playback

TODO:

• [X] Get the sound_engine running in the editor
• [X] Setup a way to sync data from Editor -> Audio Threads
• [x] Instrument Editor UIs (See Below)
• [x] "On Screen Keyboard" for testing sounds
• [x] Oscilliscope / Waveform viewer

Instrument Editors (If all of these are done, can complete the main topic above)

• [X] Ability to edit instrument types (between Wavetable, FM, Sampler, etc)
• [X] Create, Delete Instruments
• [X] General Envelope Editor Widget
• [x] FM Synth
  • [x] All editable parameters & sliders
  • [x] UI Showcase for Algorithms
• [x] Wavetable Synth
  • [x] Wavetable Generator Definition & Generation UI
  • [x] "Click to edit" Wavetables
  • [X] Draw Wavetables on UI
• [x] Sampler
  • [X] Import .wav from file
  • [X] Set Optional Frequency
  • [x] Set/Adjust Loop points

Nice To Haves (For Future Reference)

• Ability determine frequency of samples automatically, via FFT? or other algorithm.
• Better / More Flexible Oscilliscope, adjustable for viewing single channels vs entire output etc
• MIDI Integration for Piano Roll
• Clamp instrument, phrase, chain, sfx, song lengths to their maximum values.
• Better piano roll integration when editing fields

[RobDavenport]

Currently, this is what the piano roll looks like:

It's also possible to play this, as it sends events to the engine, however it's still limited to a single and uneditable instrument

[RobDavenport]

Close to finishing one of the first instruments: Wavetable synth!

Shouldn't be too long before this instrument is finished, and I expect the others will come much quicker.

[RobDavenport]

2/3 instrument editors down!