Make the scenes loadable plugins

This makes it possible to load scenes as plug-ins instead of having them
added to the main program.

Signed-off-by: Marcel Tunnissen <marcelteun@gmail.com>
Fix edges for loadable python files

Signed-off-by: Marcel Tunnissen <marcelteun@gmail.com>
Ignore tst dir
Adjust window size of Orbit Scene

Makes to the windows size for the Orbit scene suitable for smaller
screens

Signed-off-by: Marcel Tunnissen <marcelteun@gmail.com>
Add special positions for Scene_FldHeptS4

This adds some special position for Scene_FldHeptS4 that only consist of
heptagons.

Signed-off-by: Marcel Tunnissen <marcelteun@gmail.com>
Updated README with Debian

Signed-off-by: Marcel Tunnissen <marcelteun@gmail.com>