Revert "Set an ACL on ParseResource by default"

Default ACL breaks some functionalities.

This reverts commit eb437d98.

Closes #97

parse_rest/datatypes.py

@@ -255,8 +255,6 @@ class ACL(ParseType):
 
     def __init__(self, acl=None):
         self._acl = acl or {}
-        if acl is None:
-            self.set_default(read=True, write=True)
 
     def _to_native(self):
         return self._acl
@@ -319,8 +317,6 @@ class ParseResource(ParseBase):
     def __init__(self, **kw):
         self.objectId = None
         self._init_attrs(kw)
-        if 'ACL' not in kw:
-            self.ACL = ACL()
 
     def __getattr__(self, attr):
         # if object is not loaded and attribute is missing, try to load it