update readme to OSMD coastline files, base to new layer names
update coastline/land layers to OSMD in mml files
updated docs, configure.py.sample, and make.py regarding updated coastline files
correct land-low layer name for osm2pgsql.mml
moved land-low id to correct line in osm2pgsql.mml
fix typo in land-low layer selector
update readme for shapeindex, configure.py for new path to shapefiles
clean up README, make and configure
Merge remote-tracking branch 'will/coastline-fix71'

Conflicts:
	README.md