added rough_disparity_range_estimation function in rpc_utils module
added rough_disparity_range_estimation function in rpc_utils module

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