IDE improvements, fixes #209 (#117, #124)

- fixed many UI and datasource bugs/glitches in Script Editor 
- new brick selection menu (view) for adding a new brick to script (#209)
- brick cell graphics in script editor now using bezier paths for brick background (WIP)
- improvements focusing brick for editing formula  (#117)
- added edit mode in script editor view for deleting multiple bricks (#124)
- edit menu refactoring (#127)
- improved global app colours and IDE colours, updated launch image
- refactoring IDE Classes