change onchanged to take doc and newdata

oyster/core.py

@@ -178,7 +178,7 @@ class Kernel(object):
                                    })
             # fire off onchanged functions
             for onchanged in doc_class['onchanged']:
-                onchanged(doc)
+                onchanged(doc, newdata)
 
         if error:
             # if there's been an error, increment the consecutive_errors count

oyster/tests/test_kernel.py

@@ -7,7 +7,7 @@ import pymongo
 
 from oyster.core import Kernel
 
-def hook_fired(doc):
+def hook_fired(doc, newdata):
     doc['hook_fired'] = doc.get('hook_fired', 0) + 1
 
 RANDOM_URL = 'http://www.random.org/integers/?num=1&min=-1000000000&max=1000000000&col=1&base=10&format=plain&rnd=new'