doc: Write 'castxml(1)' manual
doc: Write 'castxml(1)' manual

iMichka/CastXML,thewtex/CastXML,iMichka/CastXML,ellert/CastXML,bradking/CastXML,ellert/CastXML,thewtex/CastXML,ellert/CastXML,bradking/CastXML,bradking/CastXML,CastXML/CastXML,CastXML/CastXML,thewtex/CastXML,CastXML/CastXML