offer alternative if cxxabi.h is not available
use try_compile to see if we can demangle
Build and test bpf without zlib

zlib support was baked into parts of the bpf driver, via the
`BpfSeqIterator::inflate` method and the logic in
`BpfSeqIterator::readBlock`. This patch only defines `inflate` if we
have zlib support, throws a runtime error if the bpf iterator tries to
read a block without zlib, and disables zlib tests if there's no zlib
support.

I'm not sure that my treatment of `readBlock` is correct, as for all I
know there could be a way to read a block without zlib. However, since I
don't know better, I kept things dumb and just threw an error if we
don't have zlib. @abellgithub can we do better?
Guard tests that require srs support

Add `#ifdef PDAL_SRS_ENABLED` around tests that require SRS support, and
in once case split out the srs-dependent parts of a test into a seperate
(guarded) test.

In the stats filter test, ther could be potential for simplifying those
the guarded tests to they don't depend on srs functionality. However,
that would be work for another commit.
Exclude colorization filter if we don't have GDAL

It doesn't make much sense to overlay a GDAL raster without GDAL. This
patch also reorganizes the GDAL files in src/CMakeLists.txt.
Conditionally exclude PCL

All the PCL code is now turned off if WITH_PCL == FALSE. We also remove
the command-line help text that mentions PCL.
Conditionally exclude python-dependent filters

Programmable and Predicate.
Merge pull request #365 from chambbj/issues/335-cxxabi

offer alternative if cxxabi.h is not available
Add lround for windows.
Merge pull request #379 from PDAL/issues/378-lround

Add lround for windows.
Add missing include required by lround. Closes #382
Update documentation for apps. Closes #380
Merge pull request #381 from chambbj/issues/380-apps-documentation-update

Update documentation for apps. Closes #380
Merge pull request #383 from chambbj/issues/382-include-pdal_macros

Add missing include required by lround.
add smb-shared folder for win32 clients
PCL block is in master now, Vagrant users are missing out on other improvements in master
Merge pull request #385 from chambbj/issues/384-fix-vagrant-pdal-script

Closes #384
Merge pull request #374 from gadomski/build-without-optional-components

Build without optional components
Add the rxp reader

RXP is the streaming file format used by RIEGL Laser Measuremnt Systems
(http://www.riegl.com). Support for reading rxp
files is provided by RiVLib, RIEGL's own library which they release for
use by their customers.

RiVLib only supports reading rxp files, not writing them.