Anagram: change to possible multi-word anagrams.

- Trigger reduced to "anagram of" or "anagram for" at start.
- New word list with fewer but more familiar words.

Tries to match the most popular words first.  If there's a single word
match it should fall right out at the start.

I can be talked out of the capitalization , but I think
it provides a nice notion of having been transformed.

Non-alpha are somewhat silently ignored.  I assume they'll figure it out
from the returned string.  True?

Word list sourced from million 2-grams list at
http://www.ngrams.info/free.asp.  With lots of mechanical cleaning to
purpose.  It could probably use an interested reviewer. In particular,
it contains a number of proper names and some initialisms which may or
may not be for the best.

This can hit some nasty corners where the algorithm spins for quite a
while.  Should it time out?