Firewall Builder RCS diffs

Description

The primary change is a new combo box for revision selection in the RCS check-in dialog, and supporting code in the RCS class, especially to suggest appropriate candidate revisions.

There's also change adding a config option RCS/NologOverride. If 'true' this disables the 'never prompt for RCS log text again' checkbox. Defaults to 'false.'

Notes

The patch changes the RCS locking behavior to non-strict (which loosens the relationship between locking and specific revisions, and does still use locks). I did this because I -think- that's the model we're really using. The checking-at-revision code could be made compatible with strict locking, but extra lock operations and revision computations would be required, and they seemed superfluous.

Also, the 4.0.0 beta code -- before applying these patches! -- does not always enable the RCS 'Commit' menu option which it should--i.e., when there is a change active. Again, I verified that this is happening in unpatched FWB 4.0.