Regex mode bugs due to API changes

[magnumripper]

http://www.openwall.com/lists/john-users/2015/05/08/4

I think the ?i: modifer is new in librexgen (newer than our mode), and that change probably screwed up our mode's case= feature. OTOH it also pretty much obsoletes it.

There are also other bugs (some in librexgen, some in regex mode) mentioned in the thread. We need to fix them and do some serious regression testing.

We also need to update the documentation.

[magnumripper]

This bug is obsolete. If any similar problems are present now, let's open new issues.