PSR-0 compliance

This is a PSR-0 compliant respec of the master branch (namespaces and filenames weren't syncing up previously).

PHP CodeSniffer also implies it's PSR-1 compliant, though I haven't read up terribly much on that standard.

If this is good, I'm going to merge and submit this to packagist, though @walker, I'd like to get your go-ahead before that happens.