MapGenX -> StructureX

[bs2609]

The following are all subclasses of MapGenStructure. This brings the naming more in line with ocean monuments and woodland mansions.

• EndCity
• Mineshaft
• NetherBridge (see also NetherBridge -> NetherFortress #438)
• ScatteredFeature (could be improved too?)
• Stronghold
• Village

ComponentScatteredFeaturePieces could also do with a better name.

There is a mismatch between the terms 'piece' used by the various StructureNamePieces classes, and 'component', used by MapGenStructureIO, and the abstract superclasses StructureComponent and StructureComponentTemplate. It would be nice to have some consistency here too.

[Hornwitser]

I'm not sure I like this name change that much. MapGenStructure is a subclass of MapGenBase, and the other subclasses of that base class are MapGenCaves, MapGenCavesHell, and MapGenRavine. In the ChunkGeneratorOverworld class they are all used by calling generate on instances of them. They primarily serve to generate and query structures in the world, the actual structures are stored in list of structure components/pieces in a StructureStart subclass which are in turn stored in a mapping structure inside the MapGenStructure classes.

[kashike]

• MapGen* -> *Structure