Fix spelling

Fixes PerlGameDev/SDL#259

http://anonscm.debian.org/gitweb/?p=pkg-perl/packages/libalien-sdl-perl.git;a=blob;f=debian/patches/fix-spelling;hb=HEAD
Merge branch 'experimental' of github.com:PerlGameDev/Alien-SDL into experimental
Fix more spelling and grammar
Update changelog