Bump to 2.9.0~pre4
Fix regression in general-header widget
- This prevented changing the title and description of the experiment
Udate setup.py to include new packages
Integrate fallback pool folder (__pool__) into GUI
Don't show images with [this] in the name as variably defined in sketchpad GUI
Further icon-name fixes
Don't try to extract workspace globals from non-existing experiment
- This fixes a crash when cancelling experiment startup