TLS was redesigned in more straightforward way;
OPENCV_ABI_COMPATIBILITY define was added;

Fix for bug #5007: moved definition of Size_MatDepth_t and Size_MatDepth from ts_perf.hpp to perf_channels.cpp. This way they are closer to where they are needed and live in a different namespace (possibly the reason why the fix works).

add condition to skip unmapping for internally allocated host memory. this should fix map_unmap_counting UMat test.

- load OBJ file
- set offscreen rendering
- set roll angle of the camera
- get Mat screenshot of the current scene
- remove all lights from the scene
- add a custom light in the scene
- modify the size of the WImage3D widget
- added ambient property for the widget

Changed Vec3d in cv::viz::Color

Renamed method getMatScreenshotin getScreenshot

Modified showWidget

Fixed on viz::Color and reverted fix on vtkProp3D

Removed cameraRoll method

Merged load mesh method (for ply and obj file)

Fixed doc

Fixed cv::viz::WImage3D::setSize for vtk5.8

Fixed enum for cv::viz::Mesh::load

The provided interface id must be removed from the index. Otherwise, the
underlying implementations are using a wrong camera id.

Example:
VideoCapture(800) fails because PvAPI tries to open a camera
on position 800

OPENCV_ANDROID_SDK - OpenCV Android SDK location (or OpenCV build dir)
Can be passed via ndk-build parameter or environment variable.

Command 'execute_process' from OpenCVFindMatlab module can omit error message
to the standard output. This can break build of the OpenCV package in
ExternalProject_Add (Windows/Visual Studio).