use player::recalc_hp to calculate maximal HP in newcharacter.cpp

fix scrolling out of range in the character creation stats tab
Add check for empty default ammo type when spawning matching ammo for guns
Merge remote-tracking branch 'BevapDin/fix-item-spanwammo' into FrankenMod
Merge remote-tracking branch 'BevapDin/fix-7559' into FrankenMod