Support Micro-Manager update sites

There is a special-purpose top-level directory in Micro-Manager called `OlympusIX3Control`. It is quite the fiddly thing, moving the files elsewhere might break everything, and it is hard to test whether it does because Olympus did not bother to equip the Micro-Manager team with a test system.

So let's do the next best thing (because the best solution is obviously out of our reach): bite the apple and add that specific directory as a known one to the updater. May it serve as a counter-example to hardware vendors. It is in their interest to make their hardware *more* accessible to scientists, after all, not *less*.