Merge pull request #50 from salty-horse/ds_store

Remove .DS_Store from repository
https://github.com/rmmh/PuzzleScript/commit/ea1ad1df35a921fc26bb0affce92c81636c28e95
fix documentation links for case-sensitive web servers
preserve case sensitivity rule-triggered messages, game titles, and authors. fixes #65
don't play sound when checking if we should run a turn again
fixes #64, fixes #68, fixes #69
make processInput not call redraw
rewrite graphics to use <canvas> instead of <img> for sprite storage
fix test for undefined level
update CodeMirror to v4.0. major feature: multiple selections (Ctrl-D)
color text in sprite matrix. fixes #73