Doxygen tutorials: some fixes in RST-docs
Doxygen tutorials: basic structure
Doxygen tutorials: warnings cleared
Doxygen tutorials: cpp done
Doxygen tutorials: python basic
Doxygen tutorials: python final edits
User guide converted to doxygen
Doxygen tutorials: support contrib, some minor changes
Prevent division by zero
Documentation: removed mention of Mat(IplImage*) constructor
White space and spelling in meanshift tutorial

Removed a leading whitespace from a parenthetical comment and corrected the spelling of "maybe"
Fixed typo in description of Rect operations
Python test: added options to provide local data path
Remove unnecessary kercn limitation of 4.

When accessing global memory by DWORD4, memory bandwidth
can be fully utilized on Intel platform. This patch will
make more image format(e.g. 8UC4) be processed in DWORD4
by work-item. After applying this patch, 3 subcase of
./opencv_perf_core --gtest_filter=OCL_RepeatFixture_Repeat.Repeat/*
can be speedup on HD4000 graphics card with Beignet:
OCL_RepeatFixture_Repeat.Repeat/2, 64% improvement.
OCL_RepeatFixture_Repeat.Repeat/6, 50% improvement.
OCL_RepeatFixture_Repeat.Repeat/8, 56% improvement.

Signed-off-by: Chuanbo Weng <chuanbo.weng@intel.com>
Remove unnecesary operations and calculations in loop body.

Signed-off-by: Yan Wang <yan.wang@linux.intel.com>
Use sincos instead of sin and cos.

Signed-off-by: Yan Wang <yan.wang@linux.intel.com>
It turns opengl gheck is not needed for win ctrl+s
Make Ctrl+S open save dialog on Gtk backend
Fixed whitespace warnings in new tutorials
Merge pull request #3482 from wangyan42164:ocl_brute_match_improve