Refactor / Avoidances

Refactor
Moved MGP.cs into Misc Folder
Moved GPCache.cs Into Area Folder

Avoidance
Added PosionGas to Avoidances (A2 Dying Mob / Cave Larva)
Added GrotesqueExplosion to Avoidances
Valid Units will allow non-cluster when avoiding
Added NearbyAvoidances into Combat Class
NearbyAvoidances is checked prior to testing for avoidances.
Objects tested for avoidances have a timer which assumes its still in
avoidances.
Gizmos that are being avoided will be blacklisted now.
Non-Special units will no longer trigger StayPut