New Weapon: IAF Railgun Sentry

[BenLubar]

This could be fun, maybe.

[BenLubar]

• 3 shot burst fire (0.14s between shots, so 5 rifle shots takes the same amount of time as the full burst)
• does not shoot at dead targets like the machine gun turret
• high damage (80 per shot? 120?)
• pierces infinitely (except walls and shieldbug plates) like the railgun
• 0.84s recharge between bursts (so twice as much time spent cooling down as firing)
• 300 ammo? (a little more than 2 minutes of continuous firing)