Adjustable Cannon Turret

Adds a cannon turret that uses cannon shells.

I have added settings for attack speed, range, damage, minimum range, directional fire, or 360 so you can adjust them to your liking.

Things I've fixed

• Adjusted shot starting far away from the cannon muzzle.
• Removed the extra damage research. I think the default physical projectile damage research is good enough.
• Adjusted particle effects.

Thanks to Touhma for updating this old mod and inspiring me to make my own flavor of it.