Refactor: Remove compressedChunks and related methods and data from M…

…CInfdevOldLevel and AnvilChunk

Move MCRegionFile to its own source file.
Remove knowledge of chunk structure from MCRegionFile. Rename loadChunk to readChunk.
Remove compress, decompress, unload, isLoaded, compressedSize methods.
Remove compressedTag, dataIsPacked, loadedChunkQueue/Limit, decompressedChunkQueue/Limit members.
Rename InfdevChunk to AnvilChunk. Keep in place the conversion to old-style chunks until all client code is updated.
Remove most checks for self.version and keep only the VERSION_ANVIL code in place
Rename Alpha tests to Anvil tests.
Change several tests to load the AnvilWorld test data.
Change ZipSchematic test to export an area from the center of the world instead of from hard-coded coordinates.

__init__.py

@@ -2,13 +2,13 @@
 from entity import Entity, TileEntity
 from faces import faceDirections, FaceXDecreasing, FaceXIncreasing, FaceYDecreasing, FaceYIncreasing, FaceZDecreasing, FaceZIncreasing, MaxDirections
 from indev import MCIndevLevel
-from infiniteworld import ChunkedLevelMixin, InfdevChunk, MCAlphaDimension, MCInfdevOldLevel, ZeroChunk, ZipSchematic
+from infiniteworld import ChunkedLevelMixin, AnvilChunk, MCAlphaDimension, MCInfdevOldLevel, ZeroChunk, ZipSchematic
 import items
 from java import MCJavaLevel
 from level import ChunkBase, computeChunkHeightMap, EntityLevel, FakeChunk, LightedChunk, MCLevel
 from materials import alphaMaterials, classicMaterials, indevMaterials, MCMaterials, namedMaterials, pocketMaterials
 from mclevelbase import ChunkNotPresent, saveFileDir, minecraftDir, PlayerNotFound
 from mclevel import fromFile, loadWorld, loadWorldNumber
-from nbt import load, gunzip, TAG_Byte, TAG_Byte_Array, TAG_Compound, TAG_Double, TAG_Float, TAG_Int, TAG_Int_Array, TAG_List, TAG_Long, TAG_Short, TAG_String
+from nbt import load, gunzip, TAG_Byte, TAG_Byte_Array, TAG_Compound, TAG_Double, TAG_Float, TAG_Int, TAG_Int_Array, TAG_List, TAG_Long, TAG_Short, TAG_String
 import pocket
 from schematic import INVEditChest, MCSchematic