Merge branch into blead to compile into C all POSIX classes...

This series of commits creates C compile time inversion lists for the
remaining POSIX classes that didn't have them, plus IDStart and IDCont
which are used with the 'utf8' pragma, plus one that is used for
compiling regular expressions.

This should allow faster start up times for Perl programs that use these
on code points 256 and above, while having negligible effect on programs
that don't.  It also leads to some simplification of core code, and
removal of two arrays of smaller inversion lists.