starts moving one tile in the given direction; false when already moving
Faces a direction without moving - what a bump into a wall or an NPC turns into,
rather than nothing at all. Without this, a player who arrives beside an NPC from the
"wrong" side can never turn to face it, since an actual step that way is blocked and
moveBy only ever faces the direction it successfully moves in.
Grid movement tweened between tiles, with a walk cycle - what turns "the player pressed right" into a sprite that glides from one tile to the next and faces the way it is going, rather than teleporting square to square.
This owns position and animation only. Whether the target tile is passable, whether something is standing on it, whether stepping onto it should trigger an event - all of that is a question for the map, asked before
moveByis called.Example