make gbz80disasm work with python2.6 again

There was an incompatible change to the json module api between py26 and
py27, causing gbz80disasm to not work with py26. The fix is to simply
alias the new loads method to the old read function.

A possibly better plan might be to not support py26 at all.

extras/crystal.py

@@ -13,6 +13,7 @@ import random
 # for capwords
 import string
 
+# for python2.6
 if not hasattr(json, "dumps"):
     json.dumps = json.write