fix indentation
Add Power Pills to the map.

Basic support for power pill action.

Enables 'chase mode' where the baddies can be destroyed, but otherwise
no behaviour.
Use a Vector2 to store player grid location

Technically this does mean we are storing as a float, but generally
since we're working with +1, -1 it's ok, and does make a lot of future
calculations (like distance between two points) much easier.

Really we should create a GridRef class, but hey ho. This is a step in the
right direction.
Fix player start pos
Almost working target-based AI for baddies

- get a list of each available direction at current tile
- if there is only one direction to go, go that way.
- if there are two directions to go, continue rather than reverse (unless
  stopped, since we then have to pick one)
- otherwise, we have to choose an exit - pick closest to target.

This has some bugs/TODO:

- it is easy to get stuck a loop
- need to handle the ghost house, can get stuck in there.
- there is no code to handle the gridX wrap.
Handle entityNames more clearly - abstract magic values
Abstract away access to mapData
Adjust logic so that gridRef(0,0) is at bottom left corner.

This makes it easy to use direction vector2 in combination with
gridref vector2.
add Power Pill.prefab;
Start of per-baddy state change, inc new sprites
oops - forgot to reverse Y for available cell check
playable map, def causes slowdown :(
isDead speed
DRY out
remove unused code - lastAutoDirection
Simplify turning logic
simplify movement logic
Custom scatter spot in scared mode
Handle targetting when wrapping around gridX edge
remove dead code