### Summary
- Fixes various memory leaks related to spells
- Fixes Spell Plague
- Added ability to determine if `sdi` should take effect for Spell Damage.
- Fixes animal form timer ticking non-stop while logged out.
- [X] `BaseRegion.CheckTravel` now properly cascades through parent regions
- [X] `SpellHelper.CheckTravel` now returns a failure message instead of sending one internally.
- [X] Consolidates travel restriction messages so they aren't duplicated.
