- Implemented validation for `targetCondition` in spells
- Implemented validation for `mapObject` in towns/heroes
- Fixed validation of zone connections in RMG
- Added workarounds to prevent assertions triggering on invalid mods
- Erase 'base' entries from json before validation (but after applying
them to derived keys)
Should have no effect on mod behavior/support, but may cause new
detections for mods that were broken in either 1.6 or 1.7