* use __GNUC_MINOR__ in correct place to check the version of GCC
  * check processor support of FP16 at run time
  * check compiler support of FP16 and pass correct compiler option
  * rely on ENABLE_AVX on gcc since AVX is generated when mf16c is passed
  * guard correctly using ifdef in case of various configuration
  * use v_float16x4 correctly by including the right header file

- enable C++11
- fix macro

  * enable fp16 feature correctly with gcc on x86/x86_64

  * check compiler support
  * check HW support before executing
  * add test doing round trip conversion from / to FP32
  * treat array correctly if size is not multiple of 4
  * add declaration to prevent warning
  * make it possible to enable fp16 on 32bit ARM
  * let the conversion possible on non-supported HW, too.
  * add test using both HW and SW implementation

it adds OPENCV_TINY_GPU_MODULE definition, that will allow
to build tiny version of gpu module (with limited image format support)

Also:
- Silence clang warnings about unsupported command line arguments
- Add diagnostic print to calib3d test
- Fixed perf test relative error check
- Fix iOS build problem

If used cl compiler, but generator is not Visual Studio e.g. Ninja,
enable FS option to prevent blocking PDB file in multithreaded build.

If used cl compiler, but generator is not Visual Studio e.g. Ninja,
enable FS option to prevent blocking PDB file in multithreaded build.

(cherry picked from commit 58c91356)

If used cl compiler, but generator is not Visual Studio e.g. Ninja,
enable FS option to prevent blocking PDB file in multithreaded build.

- Previous version just checked option support, but not enable it.
- Also OpenCV tests reports invalid AVX and AVX2 support status.

This flag is already added in line 131.