SWIG/Perl typemap for gdBuffer

[jleslie]

This typemap seems to get imageObj::getBytes() to work:

%typemap(out) gdBuffer %{

$result = newSVpvn($1.data, $1.size); if ($1.owns_data)

gdFree($1.data);

%}

[tomkralidis]

This may be related to #2978. Steve: any comments?

[sdlime]

Typemaps are were we need to fix things. I don't know enough Swig anymore to know if this is better than what's in plmodule.i. Although I assume what's there doesn't work so this is worth I try.

Would be nice to add an example that uses getBytes() too.

Steve