Move the behave_cscore over to its own file.
MOSES: initial scaffolding for a boosting cscore
misc minor touch-ups
More misc scoring groundwork.
Remove the multibscore code.

This code depended on earlier code that was broken and never fully
implemented.  It also had the fatal flaw of making boosting
excessively complicated.
Merge pull request #840 from linas/dmos

assorted minor changes prior to an upcoming major change