Use new style classes everywhere

Old style classes has been deprecated and should not be used
anymore

https://docs.python.org/2/reference/datamodel.html#new-style-and-classic-classes

Change-Id: I8f85f5a63af7c6500d6efcde5efe8a1fd1456ff0
Closes-Bug: #1378021
Merge "Use new style classes everywhere"