#273 XMLA Authentication

[Sujen Maharjan]

OpenI is able to connect to the xmla server anonymously. When the credentials are set in the xmla server for security, OpenI fails to connect because there is no way that we can specify credentials in OpenI. Since the security configurations in different olap servers like Mondrian and MSAS can be different, OpenI should be capable of allowing the user to specify the olap type and prompt the user for the credentials accordingly.