Set status to beta
OpenNI2: prevent failure of setVideoMode() call with invalid parameters

Not all parameters are specified for openni::VideoMode, so
"selected" mode can be unsupported for device.
Replace default VideoMode constructor to result of getVideoMode() call.
openni_capture sample: enable OpenNI2 if available

Sample works with OpenNI2 with minimal code changes (CAP_OPENNI -> CAP_OPENNI2)
PnPRansacCallback::computeError: fix count in case of Nx3 matrices
solvePnPRansac: fix mask generation
Merge pull request #3404 from alalek:openni2_patch
Merge pull request #3405 from D-Alex:master
Merge tag '3.0.0-beta'

OpenCV 3.0.0 Beta
fixed doc
Merge pull request #3408 from ilya-lavrenov:doc_fix
Fix Cuda -Wl linker options

This line causes the following error when building custom projects that use OpenCV beta 3:
ld: warning: directory not found for option '-L/<project_root>/-Wl,/usr/local/cuda'
Merge pull request #3410 from mgharbi:master