removed 2 unused strings from Maze.
Add CONTRIBUTING.md
Merge pull request #251 from nanan9177/maze_skin

Maze skin
release 0.0.37
Include blockly-core feaea36
release 0.0.38
Remove two unused strings
level -> puzzle in strings
pen -> pencil in strings
Translations
Translations
Translations
Fix alternative pluralization backends
Enable spanish builds
Full localization builds & docs
release 0.0.39
Temporarily localize to es_es only. Build output is too large :-(
Remove git advice from README
release 0.0.40
Remove unused skins