Returns all faction buffs at the given tile. These are the buffs from the current faction plus any buffs from merged factions (i.e. the neutral faction)
Returns all global buffs for the given faction
Returns all hostile buffs at the given tile. Hostile buffs are the combined buffs from all factions which are hostile to the given faciton
Recomputes the buffs
Recomputes the buffs if required
Accumulates the buffs provided by all buidings and powerups and transforms them into a grid, so that for every tile we can query which buffs for which faction are active there.