stop throwing on empty answer and solution, as there are times we could validly hit this (open level + no blocks
WIP: remove maze code, add key events
Merge pull request #385 from cpirich/bounce_wip

WIP: remove maze code, add key events
Update debug version of blockly.
Merge branch 'master' of https://github.com/code-dot-org/blockly
mutliple balls, paddle collision, bounce block
Merge pull request #386 from cpirich/bounce-day3

mutliple balls, paddle collision, bounce block
Merge pull request #384 from code-dot-org/levelTests

remove check for empty canvases
remove need for explicit ballCount, add support for multiple finishes