Add "Open with KUK360" to the context menu of supported file types

[jariq]

User reports that KUK360 doesn't appear under their right mouse button automatically like FSP viewer, PTGUI viewer and GoPro VR Player. Currently it is possible to select KUK360 via "Right click > Open with..." menu but let's take a look at what needs to be done to add an entry to the menu displayed right after the right click.