make boxfilter kernel compile on Mac GPU OCL
Add OclCascadeClassifierBuf interface
Add OpenCL stereo CSBP implementation
Fix build errors
Fix thread sync for csbp.
fix a crash on CPU OCL for some specified image sizes
Fix android tutorial 3 second picture taken bug
Calib3d documentation:
- fixed reference to Slabaugh
Changed convexHull's documentation to essentially invert the meaning of ``clockwise``.

The orientation of convexHull's result is currently the opposite of what the
documentation would suggest:

>>> import cv2, numpy as np
>>> points = np.array([[0,0],[0,1],[1,0]], dtype=np.int32)
>>> cv2.convexHull(points, clockwise=False)
array([[[1, 0]],
       [[0, 1]],
       [[0, 0]]], dtype=int32)
>>> cv2.convexHull(points, clockwise=True)
array([[[0, 0]],
       [[0, 1]],
       [[1, 0]]], dtype=int32)

Changing the function itself is probably not a good idea at this point, so
this fixes the documentation by flipping the coordinate system.

I also removed the mention of the origin, since it's irrelevant for this
function.
Fixs: After scaling back to original image, some detected ROI will outside the original image ROI
Added setting feature of FPS in cap_libv4l
Fix tuto3 picture taken crash on all devices
A modification of the JavaCameraView is needed to avoid a crash when the
app is exited. It is a good practice to remove the callback after the
stopPreview method.
Add OpenCL version 1.2 query into ocl::Context::supportsFeature().
Add backwards portability for OpenCL 1.1 when OpenCV executables
are compiled with OpenCL 1.2 profile support.
Optimize ocl::stereobm.
1. Use macro defines for some parameters(radius).
2. Reduce local memory usage.
3. Fix accuracy problem on Intel GPU.
ocl: Enable backward binary portability for setTo function.
Fix build
 add (optional) index argument to RetrieveFrame method
Suppress warning when compiling deprecated OpenCL function on GNU compilers.
some cleanup, remove some commented codes
Link to bug tracker replaced by bug description