- Added `movementCostBase` parameter to game config that defines minimal
amount of movement points that will be spent when moving from one tile
on another while offroad (and cost of Fly / Town Portal spells)
- Added `BASE_TILE_MOVEMENT_COST` bonus type that allows modifying
`movementCostBase` on per-hero basis
Example usage for hota-like pathfinding skill
```json
"tileCostReduction" : {
"type" : "BASE_TILE_MOVEMENT_COST",
"val" : -15
}
```
