Terrain types and other map changes

[jomibauer]

Add terrain types that offer stat buff/debuffs, are visually distinct, and can affect different movement types.

• [x] add terrain types
• [x] add terrain types to levelData SO and load maps from file
• [x] factor in terrain when pathfinding and getting a unit's move range
• [x] include different movement types that are affected differently by terrain
• [x] refactor new pathfinding/Movement scripts/ cleanup grid classes.
• [x] come up with a better way to discern whether a tile is in range or not.
• I'm keeping track of 'pathCost' when building a path. This means I don't need to loop through anymore to check, but there could still be a better way!
• [ ] add chest and event tiles to maps.
• [ ] Draw attack range when moving

[jomibauer]

My thoughts after getting the new "Search" based movement implemented for the first time:

The bulk of these changes are happening in the gridMap via the gridController. Also added a new component script called "movement" which does the range finding. Currently the gridMap checks that our movement is within our acceptable range, but that makes more sense as a duty of the Movement script, since it's doing all the other terrrain related stuff.

In working on this, it's clear why LiquidFire guy did the movement script the way he did. Currently things are a little tangled, and I need to do some serious thinking and refactoring to get this right. In particular, looping through the whole range list with each move input seems wasteful.