install cmake 2.8.12 from PPA
include pgpointcloud bin directory
Merge pull request #585 from PDAL/issues/583-pgpointcloud-include

closes #583
Merge pull request #584 from PDAL/cmake-2.8.12-on-travis

install cmake 2.8.12 from PPA
Port FauxReader

* introduce PDAL_ADD_DRIVER macro that creates object library for the
  given driver
* 'drivers.faux.reader' becomes 'readers.faux'
* 'pdal::drivers::faux::Reader' becomes 'pdal::FauxReader'
* headers moved from ./include/pdal/drivers/faux to ./drivers/faux
* source moved from ./src/drivers/faux to ./drivers/faux