C++ Port

[Dan Paulat]

Hello - just thought I'd share some work I did on a C++ port, including all the functionality that's with the v0.19.0 release.  My goal was to create a library I could include in a native application without including the Python runtime.  The command-line has some slight differences, but produces compatible world files and the same image types.

I've taken care to credit Bret and Federico on their great work!

https://github.com/dpaulat/worldengine-cpp

Enjoy!