Minor changes and additions to error message output strings
- CF: fixed bugs in roof routing related to handling of edge pixels when a raster
mask is present
- RHESSys: Added initial support for surface and subsurface routing tables. Surface
routing table is specified as a second file argument to the -r command line option.
If no surface routing table is specified, the subsurface routing table is used to
route both surface and subsurface flows
Merge branch 'develop' of https://github.com/RHESSys/RHESSys into develop