Add links to classes and methods and document that mk_request and mk_request_raw may raise if called before get_transport.
Add links to classes and methods and document that mk_request and mk_request_raw may raise if called before get_transport.

vishwaprakashmishra/xmatrix,vishwaprakashmishra/xmatrix,harrissoerja/vumi,harrissoerja/vumi,harrissoerja/vumi,TouK/vumi,TouK/vumi,vishwaprakashmishra/xmatrix,TouK/vumi