Changed some options:

- Templates now loaded from current directory.
- Blocks trim whitespace
- Template Syntax made explicit and line statement syntax added
Changed finalization function

- Renamed it to select_variant
- Now tuples like ('en:Hello', 'de:Hallo')
  are parsed and the preferred variant
  is selected from that.
- Added the select_variant function as a filter,
  as well.
Removed sort filter function.

Jinja2 already has one. I'm stupid.
Bugfix: Added correct function for the 'select_variant' filter.

I done goofed in accc1f3.
Added a test called 'match'.

This test uses a string like "a b -c" to determine if a collection contains a and b, but not c.