core: export getCPUFeaturesLine to bindings

modules/core/include/opencv2/core/utility.hpp

@@ -447,7 +447,7 @@ Returned value is a string containing space separated list of CPU features with
 
 Example: `SSE SSE2 SSE3 *SSE4.1 *SSE4.2 *FP16 *AVX *AVX2 *AVX512-SKX?`
 */
-CV_EXPORTS std::string getCPUFeaturesLine();
+CV_EXPORTS_W std::string getCPUFeaturesLine();
 
 /** @brief Returns the number of logical CPUs available for the process.
  */

modules/python/src2/cv2.cpp

@@ -952,6 +952,14 @@ PyObject* pyopencv_from(const String& value)
     return PyString_FromString(value.empty() ? "" : value.c_str());
 }
 
+#if CV_VERSION_MAJOR == 3
+template<>
+PyObject* pyopencv_from(const std::string& value)
+{
+    return PyString_FromString(value.empty() ? "" : value.c_str());
+}
+#endif
+
 template<>
 bool pyopencv_to(PyObject* obj, String &value, const ArgInfo& info)
 {