Added chile2010b example that goes out far enough to record DART 51406. Improved source...

Now using final USGS source and new okada2.py model. Refine more in source region.  Compare DART results to detided data.
added data for chile2010b
Cleaned up maketopo.py, removed unused functions.
Added print of Mw to read_subfault_model
Fixed README files for chile examples
improved geoclaw docs