Clean up ans_matrix in AnswerChecker.pm (mostlu cosmetic, but removes double underscore from answer extension names).
Make MultiAnswer use name prefixes that include the answer name for the initial blank (so that color.js can track them properly).  This removes the count, and makes more heavy use of the named answer rules and arrays.
Make PopUp and RadioButtons objects work properly with the new MultiAnswer name prefixes.  (These didn't work with singleResult=>1 in the past, but now do.)
Merge branch 'patch-input-colors' of http://github.com/dpvc/pg into access

Conflicts:
	lib/Value/AnswerChecker.pm
Added aria label support for multianswers