HAL: improvements

- added new functions from core module: split, merge, add, sub, mul, div, ...
- added function replacement mechanism
- added example of HAL replacement library

modules/hal/samples/simple_hal/simple.cpp

@@ -0,0 +1,34 @@
+#include "simple.hpp"
+
+int slow_and8u(const uchar* src1, size_t step1, const uchar* src2, size_t step2, uchar* dst, size_t step, int width, int height)
+{
+    for(; height--; src1 = src1 + step1, src2 = src2 + step2, dst = dst + step)
+        for(int x = 0 ; x < width; x++ )
+            dst[x] = src1[x] & src2[x];
+    return cv::hal::Error::Ok;
+}
+
+int slow_or8u(const uchar* src1, size_t step1, const uchar* src2, size_t step2, uchar* dst, size_t step, int width, int height)
+{
+    for(; height--; src1 = src1 + step1, src2 = src2 + step2, dst = dst + step)
+        for(int x = 0 ; x < width; x++ )
+            dst[x] = src1[x] | src2[x];
+    return cv::hal::Error::Ok;
+}
+
+int slow_xor8u(const uchar* src1, size_t step1, const uchar* src2, size_t step2, uchar* dst, size_t step, int width, int height)
+{
+    for(; height--; src1 = src1 + step1, src2 = src2 + step2, dst = dst + step)
+        for(int x = 0 ; x < width; x++ )
+            dst[x] = src1[x] ^ src2[x];
+    return cv::hal::Error::Ok;
+}
+
+int slow_not8u(const uchar* src1, size_t step1, const uchar* src2, size_t step2, uchar* dst, size_t step, int width, int height)
+{
+    for(; height--; src1 = src1 + step1, src2 = src2 + step2, dst = dst + step)
+        for(int x = 0 ; x < width; x++ )
+            dst[x] = ~src1[x];
+    return cv::hal::Error::Ok;
+}
+