Fixed RegExp error in IE8
Merge pull request #97 from PallasKatze/master

Fixed critical error in IE8
Add comment about IE behaviour

Encourage not regressing on this since we don't have automated browser tests yet
Add JSHint support.

Use `npm run check` or `npm run lint`.
Fix a few JSHint warnings.
.jshint.rc: Enable curly rule.
Get rid of node.js v0.9 from travis; it was buggy and not stable.
Reindent markdown.js.