default to reasonable plugin locations if PDAL_DRIVER_PATH not set
auto directory_iterator works on OSX not linux
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
Install during travis's script

This tests the install process, which has regressed at times without
test failures.
Change case in FindOracle.cmake

Before this change, "REQUIRED" was not respected.
Default BUILD_WITH_OCI=OFF if no ORACLE_HOME
Simplify oci's CMakeLists.txt

Require Oracle via find_package. Remove conditional on ORACLE_FOUND,
since find_package will abort if we don't have Oracle.
Never build OCI on travis
Allow text writer precision to be configured

This is super-dumb right now, but it allows basic precision
configuration. This is untested as the text writer test is disabled ATM.
Merge pull request #588 from gadomski/ci-test-install

Install during travis's script
Merge pull request #587 from PDAL/faux-rename-reorg

Port FauxReader
Merge pull request #589 from gadomski/default-oracle-off

Default oracle to OFF if no ORACLE_HOME
Merge pull request #586 from PDAL/auto-load-update

Auto load update
Merge pull request #592 from gadomski/text-writer-precision

Allow text writer precision to be configured