ReaLearn: Takeover mode broken

[helgoboss]

2.18.0 (in particular #1468 "Match even inactive mappings") broke takeover mode.

The reason is that targets are now always refreshed when controlling via MIDI. Before that change, targets were only refreshed for subsequent mappings matching the same source.

Two things should be fixed here:

1. The actual regression (don't refresh targets if not necessary!)
2. Try to make takeover mode work even if targets are refreshed (for subsequent mappings)