Religious update

These are the modifications I have made to speed up conversion of pagans. The aim of the changes was to facilitate a gradual conversion of pagans that already has some effects in the 9th-10th centuries and speeds up as time goes by and the pagan world weakens. Due to the difficulty of testing CK2+ (i.e. it takes a long time to run a game from 867 to the 1000s), the test sample for this set of changes is quite small, but what I have so far seems to be fine. Currently, the rate of conversion should be slightly slower than before CK2+C, but much faster than before this change.