GD.pm6 - Interface to the GD graphics library

GD.pm6 is a Perl 6 interface to Thomas Boutell's GD graphics library.
GD allows you to create and manipulate images using a large number of
graphics primitives, and emit the drawings as PNG or JPEG files.

The API is designed to match that of the Perl 5 library, to simplify the
translation of Perl 5 GD programs to Perl 6.

GD.pm6 depends on NativeCall.pm6 from Jonathan Worthington's Zavolaj
project.  It extends the initial proof of concept code found in the
gd2-basic.p6 script in Zavolaj's examples directory.