Split up markdown-js into multiple files, uses Grunt to produce browser distribution.
Replace tabs with spaces
jshint: Enforce 2 space indent.

Having switch and case at the same level wouldn't have been my choice but it
doesn't appear configurable and I'm not too fussed about it, so I'd rather have
checking with this one minor downside than not
Update grunt instructions to work when grunt isn't installed globally
Change log entry for grunt build/split files
Split up markdown-js into multiple files, build system assembles from them for web use.