* bgr2gray 8u fixed to be in conformance with IPP code

* coefficients fixed so their sum is 32768

* java test for CascadeDetect fixed: equalizeHist added

Do not try to process empty inputs.

- eliminate rand() calls
- non initialized members/ variables
- unused return values
- missing/useless NULL checks

color.cpp split (#10869)

* initial split is done

* files renamed (these names are excluded during compilation)

* IPP code moved to corresponding files

* splineBuild, splineInterpolate -> color_lab.cpp

* Lab, Luv: little refactored

* it compiles (didn't check work); Lab OCL code moved to color_lab.cpp

* cvtcolor.cl: Lab/Luv part moved to color_lab.cl

* cvtcolor.cl: color_rgb.cl extracted

* cvtcolor.cl: color_yuv.cl separated

* cvtcolor.cl: color_hsv.cl extracted

* cvtcolor.cl: extracted to color_lab.cl and color_rgb.cl

* helper functions moved to hpp file

* Lab, Luv: moved to color_lab.cpp

* CPU XYZ: to color_lab.cpp

* OCL XYZ: to color_lab.cpp

* warning fixed

* CvtHelper added

* CPU YUV: to color_yuv.cpp, helpers to color.hpp

* CPU HLS/HSV: to color_hsv.cpp

* CPU BGR2BGR: to color_rgb.cpp

* CPU RGB: to color_rgb.cpp

* extra arg removed

* CPU YUV: to color_yuv.cpp

* color code decoded

* OclHelper added, some funcs rewritten

* color_lab.cpp: refactored to use OclHelper

* OCL RGB: to color_rgb.cpp

* OCL HLS/HSV: to color_hsv.cpp

* OCL YUV: to color_yuv.cpp

* OCL YUV planes: to color_yuv.cpp

* OCL: color code reduced

* licence to demosaicing.cpp

* IPP func tables to color_rgb.cpp

* code cleanup

* HAVE_OPENCL ifdefs added

* helpers made more common

* fixed two plane YUV with separate mats

* fixed warning in gcc7.2.0

* precomp header fixed

* color space classification functions fixed

* helpers fixed

* rename: isSRGB -> is_sRGB