Corrected some logic in the culture conversion and inheritance cleanup effects

Fixed some stuff regarding steppe and desert buildings and culture conversion
(made sure that the shuttered modifier gets cleared if a culture change invalidates buildings)

Fixed an error that I introduced, which had probably made it impossible to build Peace and Murder bloodline buildings

Moved the shuttered building conditions into scripted triggers

For shutter and downgrade decisions, added requirement that the barony's levies not be raised

Incorporated various changes that were introduced in v 3.1 (sorry for the delay)

Updated for v 3.0

Moved the holding modifiers into their own file instead of appended to the end of the 00_event_modifiers.txt file

only added a couple of steam workshop tags