Command line works now.

The script "run.sh" loads or creates and saves a planet. The UWP of the planet is
then displayed.
Improved main program handling.

Now the main program can better pass parameters to the World
constructor.
Merge branch 'feature/AllowCommandLineInputForPlanet' into develop
Markdown and HTML generation now work.

There is an issue with the code page of the HTML generation; however,
the HTML generated by markdown only contains the payload. I will have to
create a HTML wrapper with the codepage anyway.
Finish Markdown