New features:
* Mirror an entity at the core/center along each of the axis.
Logic links will be mirrored, too. But docked entities are not mirrored.
* Smd2 file support, except some exotic variations.
If you find one of those exceptions, I need an example blueprint to add support of them.
For proper smd2/3 conversion the StarMade blockconfig is required and can be added using the '-sm' argument, pointing to the 'StarMade' folder.
Without the '-sm' argument many blocks types will end up with 1 hit point when converted.
* Python3 is now supported
Bug fixes:
* Setting block orientation bits should now work right.
* Statistics info in 'header' file is now handled right when changing entity type.
* Chunk16/32 is now determined for each file type independently.
* Many other minor issues...