Fix invocant-unshift handling.

Was exposed by wrap.t, but could have come up in a variety of ways.
Fixes to ischarprop.

Unbusts /<:L> \w*/ regex used by wordcase, thus fixing it.
Fix failure to reach type_accepts type check mode.

This was behind various of the parametric roles failures in Rakudo.
bump VERSION to 2013.07
Added chdir with helpful error message for JVM