backend/textmate: Fixes for go1.3-ish map changes.

Previously (by chance!) the map[string] keys happened to be ordered
in the expected order, but this appears to not be a given with
go tip at the moment.

This change fixes the assumption of order by explicitly sorting
where order is important.
travis: Add rubex directory to PKG_CONFIG_PATH search directory.

As apparently libonig-dev doesn't contain a .pc file. Should fix
issue #263.