Update SDL bindings to SDL 1.2.13

[kthakore]

Have to accumulate what is missing and add those binding.

[jtpalmer]

Aren't we on 1.2.15 now? Anyone know if this can be closed?

[jjatria]

Yes, it looks like this distribution is already using 1.2.15:

$ perl -Ilib -MSDL -MSDL::Version -E '
    printf "%s.%s.%s\n", map { $_->major, $_->minor, $_->patch } SDL::version
' 
1.2.15

I think this issue can be closed.