Fix up testing. Add in a few missing editor methods.
Merge branch 'blockly' of github.com:Khan/live-editor into blockly
Add in missing getCursor method.
Get image picker working for reals

Test Plan:
- Drag display image, pick new image, reload page
Add No-return function call block
Generic Call Expressions - dont trample p5 calls
Look for and Register function declarations, so we can use their arg labels in func call blocks