Performs the MyTradeMe method: Retrieve a list of items currently for sale
using the "query" string provided - should be the "MyTradeMe/SellingItems/All.xml" part of the url. It shouldn't include "http://api.trademe.co.nz/v1/".
public Items SellingItems(string query) { var getRequest = _connection.AuthenticatedQuery(query); var xml = getRequest.ToString(); return Deserializer<Items>.Deserialize(new Items(), xml); }