Started port of TST

I am porting my Ternary Search Trie to go for a string indexing.

See:
http://hackthology.com/ternary-search-tries-for-fast-flexible-string-search-part-1.html

Also see: http://github.com/timtadh/tst

Signed-off-by: Tim Henderson <tim.tadh@gmail.com>