Add compatibility module.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/common/compat.py

@@ -0,0 +1,25 @@
+from __future__ import unicode_literals
+
+import sys
+import types
+
+# Useful for very coarse version differentiation.
+PY2 = sys.version_info[0] == 2
+PY3 = sys.version_info[0] == 3
+PY34 = sys.version_info[0:2] >= (3, 4)
+
+if PY3:
+    dict_type = dict
+    dictionary_type = dict
+else:
+    dict_type = types.DictType
+    dictionary_type = types.DictionaryType
+
+try:
+    from email.Utils import collapse_rfc2231_value
+except ImportError:
+    from email.utils import collapse_rfc2231_value
+
+
+
+