Remove Obsolete Classes after git branch switch

[dieknolle3333]

Whenever you locally change your git branch in Algernon, a lot of Obsolete Classes (classes that existed in the old branch but not in the new one) are still around and show up in the search results.
A reasonable goal could be to find out why that is and making sure that no Obsolete Classes are shown immediately after the switch (in Algernon) without abandoning and reopening Algernon or reloading the cache in the image.