Cleaned up geoclaw/examples for use in the gallery, and added fgmax routines to Makefiles.
Added README.rst files to geoclaw/examples directories and removed .txt versions.
Added new optional parameter geo_data.manning_coefficient_onshore and geo_data.friction_shore_level to data.py and modified source term code to allow a different Manning coefficient onshore.
improved examples of fgmax in dev/ and added README files