Anagram: require connector words for context.
Anagram: allow for multiple word inputs.

- Cache by default; only turn off for "scrambled" results.
- Simplify `calc_freq` slightly.
- Remove "length" argument, as it doesn't make sense with anagrams.
- Cache letter frequency info as dictionary words are examined.
- Allow for multi-word queries to match single word anagrams.

This still does not allow for multi-word anagrams.  Although it
would be nice to do so, it adds significant computational complexity.
Anagram: allow for bare keywords.

I'm depend on trigger order continuing to be important.  If you got here
via bisect, I am sorry that is no longer true.
Anagram: HTML encode scrambles.

Although this isn't _exactly_ a user-supplied string, it is still
somewhat under their control.  Better safe than sorry.

Thanks to @mintsoft for the suggestion.
Merge pull request #667 from mwmiller/anagram_rethink

Anagram: allow for multi-word queries.