Remove effectively dead make-message-exception, and related cleanups

In -library mode, check blocks were not being dropped because the
no-checks-visitor wasn't visiting nested blocks.  Fix that.

Also, noticed that the check block in test-binops was never being run while
doing this, so unwrap and fix that
rebootstrap with no make-message-exception
parse-test also depends on these two files
Prevent - at end of identifiers, closing #222.
 - Add tests to warn on regression.
 - No regex constructions that aren't already in use are used in this fix.
   Hopefully this implies no new browser incompatibility.
Allow multiple hyphens in a row, and add more parse tests
Use Ben's regex