Add doc generation to Travis build script
Merge pull request #421 from taketwo/add-doc-generation-on-travis

Add doc generation to Travis build script
Upload generated docs from Travis to Github

based on https://gist.github.com/douglasduteil/5525750
Travis setzt TRAVIS_PULL_REQUEST to 'false' not empty
Fix Travis pull request logic
Fix rst indention
Use shared_ptr in planar_segmentation tutorial

Fixes "Unhandled exception at 0x55e7b1cc (mscvr100d.dll) in :
Plane_fitting: 0xC0000005: Access violation reading location
0xffffffffffffffff." on Windows
add cmake options to enable/disable optional dependencies

This commit adds
- WITH_LIBUSB
- WITH_OPENNI
- WITH_FZAPI
- WITH_PXCAPI
- WITH_PNG
- WITH_QHULL
- WITH_CUDA
- WITH_QT
- WITH_VTK
- WITH_PCAP
- WITH_DOCS (doxygen documentation)
- WITH_TUTORIALS (Sphinx tutorial documentation)

Phew, this project has quite a number of optional dependencies..

With this change it's possible to build pcl without optional dependencies
even though they are available on the system.
Merge pull request #476 from v4hn/optional-dependency-flags

add cmake options to enable/disable optional dependencies
Fix test/CMakeLists.txt when building without visualization