Completes fixing #315

Adds some checking to compare the state of the "History Selected" flag (UNKNOWN_FLAG_NUMBER_00418 is set once a history is initially selected, to prompt older saves from prior to History perks being a thing to select one) versus incoming History perks in save data.
If the flags set and no history perk has been found, it's assumed that History: Whore has been previously stripped from the save, and needs to be re-added to the characters perk list.