Auto-possessify OP_CLASS and some other bugfixes.

git-svn-id: svn://vcs.exim.org/pcre/code/trunk@1382 2f5784b3-3f2a-0410-8824-cb99058d5e15
Allow auto-possessify to check more complex bracketed expressions.

git-svn-id: svn://vcs.exim.org/pcre/code/trunk@1383 2f5784b3-3f2a-0410-8824-cb99058d5e15