Pointer cursor on widget hover, remove some debugging stuff
Add .DS_Store to .gitignore
Make line re-eval on locking, not just unlocking. Minor interface tweaks (free numbers can't be scrubbed, link button is disabled).
Update .gitignore to ignore emacs temp files
Make unary minus actually parse correctly
Big rewrites -- unary minus now works. Track positions and number tokens in the parse phase, then use the parsed tokens for hover/scrub targeting instead of the lexer's tokens. Also, get rid of unnecessary mark tracking logic and just use CodeMirror (because we only use replaceRange instead of overwriting lines, we don't need to worry about overwriting marks anymore). Remove unit support, because I wasn't even trying to maintain it.
Remember to reparse and avoid getting into weird states. Slightly better free number placeholder. Everything seems to work?