Update Greyhound driver.
Merge pull request #448 from PDAL/noiter

Remove iterators from pdal readers
Update overview for readers.
Add missing image.
Merge branch 'master' of https://github.com/PDAL/PDAL
Add tree depth query to QuadIndex.
Reorganize test data #441
Fix RST.
Merge branch 'master' into rxp-driver

Conflicts:
	src/StageFactory.cpp