Add maze builder functionality.
Merge pull request #458 from code-dot-org/i18n

If a translation is not provided, use English.
some flappy code cleanup
fix directory name (mooc -> blockly) in readme
fix dev build command for blockly
add solutions for the rest of stage2/maze
Remove umbrella repo note, add contributing note
solutions for stage 9 (karel levels)
Merge pull request #459 from code-dot-org/flappyImprovements

some flappy code cleanup
[Progress on 67046576]: add sharing to Bounce
Merge branch 'master' of https://github.com/code-dot-org/blockly into pivotal_67046576
stage 13 solutions
[Finishes 67046576]: Enable bounce sharing
cosmetic flappy changes: adjust share button height, don't draw square or border around 400x400 image
Merge pull request #460 from code-dot-org/pivotal_67046576

Pivotal 67046576: enable sharing of bounce - on new last level
tests for stage 7 (artist)
Inline Cairo/node-canvas instructions

This has been a common stumbling point and general annoyance during setup. Moving the prerequisite note above install instructions.
Fix path for build dir.
Merge pull request #461 from code-dot-org/levelTests

Add a bunch more test solutions
add simple move blocks, clean up turtle movement logic a bit