add xml parsing of digitalglobe rpc.xml files in C
add xml parsing of digitalglobe rpc.xml files in C

dyoussef/s2p,dyoussef/s2p,MISS3D/s2p,mnhrdt/s2p,jmichel-otb/s2p,dyoussef/s2p,carlodef/s2p,jmichel-otb/s2p,mnhrdt/s2p,jmichel-otb/s2p,dyoussef/s2p,MISS3D/s2p,MISS3D/s2p,jmichel-otb/s2p,carlodef/s2p,MISS3D/s2p