Add list_XXX in Service Bus Service Management API wrapper

The idea is described here: https://github.com/Azure/azure-sdk-for-python/issues/168

This adds:
- Description objects for Topics, Queues, Notification Hubs and Relays
- New methods in "servicebusmanagementservice.py"
- Improvement of "_convert_response_to_feeds" which can now take a WindowsAzureData as callback (in replacement of a convert function) and use the reflective code to populate the object
- Improvement of "_get_entry_properties" with a new parameter which extract "name" from "entry/title" and not "entry/id" parsing
- 4 unit tests (one for each list_XXX) which call the list_XXX method, but do not check the objects (since I cannot be sure that for each account one of these objects exists)

Unit tests of "servicebusmanagement" checked on Py2.7.6 and Py3.4.1. But since these unit tests do not test the content of the object itself, it might not be enough on Py2.7.6 (I tested my personal objects fully on Py3.4.1)