Add two new events to the player class (tank & level)

[Cazka]

This PR closes #13

Added:

• Event - "level": This event is triggered when the player level changes.
• Event - "tank": This event is triggered when the player tank changes.

Note: When another player has his name as "Lvl x y" (e.g. Lvl 16 Sniper) those events will also trigger.