[BF4] player type

`admin.listPlayers` include the field `type`. This feature is not yet documented by DICE. I saw it by chance. This return what the player is. I have examined the behavior.

|  | type | description |
| ------------- |:-------------:|:----- |
| BF4_PLAYER | 0 | normal player |
| BF4_SPECTATOR | 1 | spectator which is not visible in the game for other player but visible as player for b3 |
| BF4_COMMANDER | 2 | commander which is visible for other player and b3 |

- add properties `is_commander` and `get_player_type` to Clients