Update 0.2.1

Major changes:

• new fireflies flying arond the position of the character on the screen of non-active player
• new option in the menu for the host to choose his color for the first level played
• players exchange their colors every levels by default
• return to main menu by typing "escape" (use to restart level)

Minor changes:

• the "ip adress" field for the client keep in memory the last entered ip adress to save time when restarting a level
• levels have been improved to fix some "soft lock" problems

Known issues:

• Sarting the client before the server is active will block the game that will need to be restarted