Balance tweaks + one bugfix

-Fixed a bug which had a chance of causing a missing boss in endless mode -Stuns from lightning/plasma weapons last a little longer -Fire damage over time is a little stronger -Radioactive projectile weapon ammo does a bit less damage -Dreadnought turrets have less health -Disintegrator beam is a little longer -Photon rounds are now much more accurate and have very strong knockback -Shockwave sprite on explosions is a bit bigger -Safety ammo now has more splash radius -Nuclear missiles can now use safety ammo, have fun nuking yourself!