Added operator for Rhubarb lipsync

[Banbury]

Rhubarb Lipsync is a tool to generate lipsync data from audio files automatically. It's much easier to use than Papagayo. This change adds an operator to load data files from Rhubarb and generate keyframes from them.

• Create a tab-separated lipsync file with Rhubarb Lipsync.
  https://github.com/DanielSWolf/rhubarb-lip-sync
• Create a sprite image with the mouth shapes as frames ascending from A to X.
  See Sample Files/ken-mouth.png
• Load the sprite into Blender with Coa Tools. Try switching the mouth shapes
  with frame_index
• Start the Rhubarb Lipsync operator via the spacebar menu or press the button
  'Lipsync' in the Coa sidebar. Make sure the mouth sprite is active.
• Select the lipsync file in the operator properties. Keyframes are generated
  for the mouth sprite. The animation will be resized to contain all
  keyframes.
• If "Start at current frame" is checked, the keyframes are added at the current
  frame. Otherwise the keyframes start at frame 1.

[tynrare]

So, 7 month… Develop, dead?

[Banbury]

@Tymonrare It wasn't dead in January. Nobody commented, it wasn't merged. So I thought, there's no interest.

[blurymind]

I think @ndee85 would need to review the code

[Banbury]

After a year I'm not going to hold my breath.