updates rdf example to version 1.2

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>
Moves builder exceptions into their own module

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>
Initial rdf parser module with document fields only

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>
Implements rdf DocBuilder

Signed-off-by: Ahmed H. Ismail <ahm3d.hisham@gmail.com>