Accumulated changes

Nothing directly user-visible but the Wiz0x0002 form code has been completely rewritten since the last release. It's now far more re-useable (most of it having been moved into BhavWiz.cs), which means the BHAV Operand Wizard is more likely. Also on that front, Tunaisafish did some investigation into BHAV operand passing, which has been incorporated.

A final note: the tree now has me committing most changes to the "PreRelease" branch, leaving HEAD with the latest "publically announced release". The means I don't have to worry about situations like 0.53b_qa to 0.53c_qa where Quaxi built the plugins. (Had I had semi-finished code in HEAD, I'd have had nightmares!)