Modified 'mc_project_get_categories' soap api call to return id & name

Modified 'mc_project_get_categories' soap api call to return id & name rather than just an array of the names.
-this wouldn't work without adding 'WSDL_CACHE_NONE' to the soap server parameters (not sure why)

Considering categories are submitted by their id, I found it a bit baffling that getting a list of the categories for a project did not include the ids.. This should return both.