Use new-style classes so properties work

Properties don't work on old-style classes.  Convert classes to
new-style by explicitly inheriting from object.

materials.py

@@ -4,7 +4,7 @@ from materials import classicMaterials, materials
 from numpy import *
 NOTEX = 184
 #wow, punching this map in would have been much easier in hex
-class MCMaterials():
+class MCMaterials(object):
     def materialNamed(self, name):
         return self.names.index(name);
 

mclevel.py

@@ -269,7 +269,7 @@ def decompress_first(func):
         return func(self, *args, **kw);
     return dec_first
     
-class MCLevel:
+class MCLevel(object):
     """ MCLevel is an abstract class providing many routines to the different level types, 
     including a common copyEntitiesFrom built on class-specific routines, and
     a dummy getChunk/getPresentChunks for the finite levels.
@@ -1188,7 +1188,7 @@ class PlayerNotFound(Exception): pass
 class ChunkNotPresent(Exception): pass
 class ChunkMalformed(ChunkNotPresent): pass
 
-class ZeroChunk:
+class ZeroChunk(object):
     " a placebo for neighboring-chunk routines "
     def compress(self): pass
     def load(self): pass

nbt.py

@@ -23,7 +23,7 @@ import StringIO;
 from numpy import array, zeros, uint8, fromstring
 TAGfmt = ">b"
 
-class TAG_Value:
+class TAG_Value(object):
   """Simple values. Subclasses override fmt to change the type and size. 
   Subclasses may set dataType instead of overriding setValue for automatic data type coercion"""