Added some documentation

Documented the tokenize function.
DRY'd the code some

Added a function to grab literals and tag keys,
since the code was very similar and in two places.

Also the grab_literal function is probably more efficent,
as it doesn't peek so much.
Fixed "no escape?" bug

Triple brace tags were yielding "no escape?" instead of "no escape".
Stopped tokenize from yielding comment tags
Added a render function

Render takes a template and data dictionary and returns
a mustache rendered string.

Also updated the test.mustache and added a partial.mustache file.