PDAL/PDAL — pull request #259 by chambbj (2014-03-26 17:24:13+00:00)
Title: Begin using 'option' rather than 'set' for PDAL options

Options become slightly more concise (drops the ```CACHE BOOL```) and
enables use of ```CMAKE_DEPENDENT_OPTION``` macro, which could be useful
for ```GDAL```, ```GeoTIFF```, and ```TIFF``` among others.