Add a random iterator for the sbet reader
Use getFieldAs to properly convert values from a PointBuffer when writing
output.
fix #314 -- respecting 'format' option instead of forwarding metadata if set
Merge pull request #316 from PDAL/issues/296-las-write

Use getFieldAs to properly convert values in writers.
Merge pull request #314 from PDAL/issues/314-las-writer-pointformat

drivers.las.writer uses metadata instead of option when 'format' is set
Merge pull request #315 from gadomski/sbet-reader-random-iterator

Add a random iterator for the sbet reader
Merge branch 'master' into rxp-driver