* rewrote Mat::convertTo() and convertScaleAbs() to wide universal intrinsics; added always-available and SIMD-optimized FP16<=>FP32 conversion

* fixed compile warnings

* fix some more compile errors

* slightly relaxed accuracy threshold for int->float conversion (since we now do it using single-precision arithmetics, not double-precision)

* fixed compile errors on iOS, Android and in the baseline C++ version (intrin_cpp.hpp)

* trying to fix ARM-neon builds

* trying to fix ARM-neon builds

* trying to fix ARM-neon builds

* trying to fix ARM-neon builds

* trying to fix the custom AVX2 builder test failures (false alarms)

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* fixed compile error with CPU_BASELINE=AVX2 on x86; raised tolerance thresholds in a couple of tests

* seemingly disabled false alarm warning in surf.cpp; increased tolerance thresholds in the tests for SolvePnP and in DNN/ENet

* Remove a forward method in dnn::Layer

* Add a test

* Fix tests

* Mark multiple dnn::Layer::finalize methods as deprecated

* Replace back dnn's inputBlobs to vector of pointers

* Remove Layer::forward_fallback from CV_OCL_RUN scopes

Signed-off-by: Zhenqing Hu <huzq85@gmail.com>

Commits:
- 09837928
- 10fb88d0

Excluded changes with std::atomic (C++98 requirement)

Currently the private control enumeration will be stopped when QUERYCTRL
returns -EINVAL only. It is possible however that other errors occur.

One particular case is when the v4l2 device doesn't support any controls
and doesn't implement the QUERYCTRL ioctl. In that case the v4l2
framework returns -ENOTTY. In that case the current control enumeration
will go in an endless loop.

To fix this change the control enumeration stop condition. If any errors
occur, end the control enumeration.
Signed-off-by: Todor Tomov <todor.tomov@linaro.org>

- don't use TBB in samples

- support passing of `std::vector<KeyPoint>` via InputArray