Clarified assert message for allowed PnP flags

Matlab bindings: CMakeLists.txt: use "${LIBRARY_OUTPUT_PATH}/${CMAKE_CFG_INTDIR}" as MEX_LIB_DIR only when compiling with MSVC, otherwise, use only "${LIBRARY_OUTPUT_PATH}"

Matlab bindings: fixed the functional template to perform an explicit cast to the type of an input option that is expected. This avoids issues with ternary operator not having the same type in rvalue and lvalue, such as in the case below:

Ptr_FeatureDetector blobDetector = inputs[3].empty() ? makePtr<SimpleBlobDetector>() : inputs[3].toPtrFeatureDetector();

Which after the patch, would be:

Ptr_FeatureDetector blobDetector = inputs[3].empty() ? (Ptr_FeatureDetector) makePtr<SimpleBlobDetector>() : inputs[3].toPtrFeatureDetector();