Changeset 4482

Modifing testrouting to make it work for XIOS. Finding the usable GRDC observation stations by comparing upstream basin area and distance between GRDC and model subbasin. The GRDC and the corresponding model subbasion information (Lon, Lat, Area, Discharge, etc.) is then written into river_grdc_XXXX.nc output. This nc file also contains the information of the pre-defined number of largest river basins. Another output grdc_river_desc.nc describes the all the matched GRDC river basins (for post-processing).