Grammar for new language, Rip

Some class names are unrecognized (date, time, datetime, maybe more). I'm not sure how to address that. Also I didn't do anything fancy with `inside` (I haven't fully wrapped my head around how to use it), even though some parts of the grammar would be improved if I had.

A test file can be found at https://gist.github.com/ravinggenius/75af019d62c8dc80a703. Feedback is welcome.