Add sling attachment to the Trebuchet
Added TrebuchetProjectile class using simple bezier curve
Add Position to DamageInfo for Plague Barrel
Increase damage for TrebuchetData and remove EggFlags.Mobile from valid target
Allow Bombs to attack any IDamageable not just EggGroup types
Add TrebuchetData to test egg set
Add Trebuchet entity and fire a projectile every 5 seconds (test)