V1.5.1 Hotfix

This version mostly just has small fixes and damage tweaks. Nothing groundbreaking.

• Trenchgun got a slight buff, as one of the 11 pellets deals 15 damage and is nearly perfectly accurate.
• Rusty carbine got its damage lowered by 1 point. Shouldn't matter much.
• Dual MGs now have the same damage profile as the Skullcracker (20*D3) damage.
• New sprites for the megasphere and backpack. Nothing crazy, but they'll fit in now.
• New help and credit screen by Skelegant.
• Credits list updated, missed a couple credits in 1.5. Oops.

That aside, I think the mod is in a good spot now. This may be the last update for a while.