Combining decoding and matching

[Dmitry Olshansky]

Following up on D parsing thread I had sometime to experiment with 
decode-less matching of full Unicode code point range.

The end result is very pleasant, I'm still benching it but it shows 
great speed up already. Without further ado:

Pull & peek at preliminary results
https://github.com/D-Programming-Language/phobos/pull/1685

Docs
http://blackwhale.github.io/phobos/std_uni.html#MatcherConcept

Caveats: like it's 'backend' std.uni Trie it suffers from poor 
performance on DMD. Kudos to LDC team, or I'd gave up on the whole idea.

-- 
Dmitry Olshansky