Adds friendlier debugging for ionPyDict. (#144)

amazon/ion/core.py

@@ -630,6 +630,16 @@ def __iter__(self):
         for key in six.iterkeys(self.__store):
             yield key
 
+    def __str__(self):
+        return repr(self)
+
+    def __repr__(self):
+        str_repr = '{'
+        for key, value in self.items():
+            str_repr += '%r: %r, ' % (key, value)
+        str_repr = str_repr[:len(str_repr) - 2] + '}'
+        return six.ensure_binary(str_repr) if six.PY2 else str_repr
+
     def add_item(self, key, value):
         if key in self.__store:
             self.__store[key].append(value)