Weapon Selection

At this time I hardcoded numbers 1-6 to be the weapons we currently have
available. you can see that in level.cs. If you click numbers 1-3 you
change your primary weapon, if you click 4-6 you change your secondary
weapon.

I have not done the scroll wheel yet but it should be an easy
implementation. I just wanted to check how everyone wanted it
implemented.

Please let me know if there are any problems