Update SDKROOT environment variable name in Pygame.

Change introduced in cf235607.
Adjust environments for Xcode 5 toolchain.
Adjust libjpeg-turbo build script for Xcode 5 toolchain.
Adjust Python build script for Xcode 5 toolchain.
Adjust sdl2_ttf build script for Xcode 5 toolchain.
Update docs to indicate Xcode 5.1.1 requirement.
Merge branch 'xcode-5'
Fix that release config was appended to debug config instead of replacing it.
Only run full fat binary build after an 'all' build.
Note that nasm is a build requirement.
Fix comment typos.