dispatch accumulate series

- use universal intrinsic for base
 - dispatch for float/double version using AVX
 - AVX2 optimization not done yet

modules/imgproc/src/accum.dispatch.cpp

@@ -0,0 +1,20 @@
+ // This file is part of OpenCV project.
+// It is subject to the license terms in the LICENSE file found in the top-level directory
+// of this distribution and at http://opencv.org/license.html.
+
+#include "precomp.hpp"
+
+#include "accum.simd.hpp"
+#include "accum.simd_declarations.hpp" // defines CV_CPU_DISPATCH_MODES_ALL=AVX2,...,BASELINE based on CMakeLists.txt content
+
+namespace cv {
+
+DEF_ACC_INT_FUNCS(8u32f, uchar, float)
+DEF_ACC_INT_FUNCS(8u64f, uchar, double)
+DEF_ACC_INT_FUNCS(16u32f, ushort, float)
+DEF_ACC_INT_FUNCS(16u64f, ushort, double)
+DEF_ACC_FLT_FUNCS(32f, float, float)
+DEF_ACC_FLT_FUNCS(32f64f, float, double)
+DEF_ACC_FLT_FUNCS(64f, double, double)
+
+} //cv::hal