Add two autotests
- The first test makes sure that the width of the places panel doesn't change no matter what other panels are shown or hidden. There used to be bugs about this.
- The second test is kind of an integration test. It makes sure that the go actions work correctly. On two occasions we had the regression here that after going "Up" in the file system hierarchy the folder one emerged from didn't have keyboard focus which makes peeking into multiple folders tiresome. The test also makes sure that going back and forward works as expected and there are some sanity checks about which go actions are enabled, which items are selected and that using tabs doesn't interfere with any of that.