Stereo phaser.

Several issues:
- slow
- need background image
Cosmit
Changed some default parameters for the compressor and the expander + changed the pipeline a little bit. It should filter the gain signal a little bit better, although it's in another dimension, so who knows...
Merge branch 'develop' of https://github.com/mbrucher/ATK-plugins into develop
Merge branch 'release/ATKCompressor-1.0.1'