Assigning a default context argument actually creates a global, which I don't…

Assigning a default context argument  actually creates a global, which I don't think was the intended effect.  More discussion and a better explanation of this can be found at http://bit.ly/1iw46

pystache/template.py

@@ -9,9 +9,9 @@ class Template(object):
         '!': 'comment'
     }
 
-    def __init__(self, template, context={}):
+    def __init__(self, template, context=None):
         self.template = template
-        self.context = context
+        self.context = context or {}
 
     def render(self, template=None, context=None):
         """Turns a Mustache template into something wonderful."""

pystache/view.py

@@ -15,9 +15,9 @@ class View(object):
     # Contents of the template.
     template = None
 
-    def __init__(self, template=None, context={}, **kwargs):
+    def __init__(self, template=None, context=None, **kwargs):
         self.template = template
-        self.context = context
+        self.context = context or {}
         self.context.update(kwargs)
 
     def load_template(self):