Minor explosion weapon sound fixes
Adds Explode weapons for ships and submarines
Adds visible explosions to ships and submarines
Adds Explosions to all vehicles that didn't have one.
Fix stupid typo, use UnitExplodeSubmarine for MSUB.
Fix typos in vehicles.yaml
Merge pull request #5091 from reaperrr/ra-vehicle-explosions

Add RA vehicle explosions
Fixes #5077
Upgrade to SDL 2.0.3 and latest SDL2-CS (e8731ef).
Fix a visual glitch in OSX.
Add changelog entry.