update a number of documents (PCL, deprecated filters, etc.)
update example to point-context-schema (no filters.scaling anymore)
add additional classifcation field option to drivers.nitf.writer
Allow build on Boost 1.56
Merge pull request #471 from pramsey/boost56

Allow build on Boost 1.56
Merge pull request #469 from chambbj/doc-updates

update a number of documents (PCL, deprecated filters, etc.)
Add undoc'ed options for pgpointcloud writer
Merge pull request #472 from pramsey/pgdoc

Add undoc'ed options for pgpointcloud writer