Supporting System.Serialize Types.

This is how I used it:

Vector3 pos = playerGameObjects[index].GetComponent<Transform>().position;
players[index].SetState("posX", pos);

and to get:

 var newPos = players[i].GetState<Vector3>("posX");
 Debug.Log(newPos);

Result of Test build:

shows vector3 position of the player.

These changes didn't break anything else (currently only tested with Vector3).

Should resolve #32 and #20.

asadm / playroom-unity