Fixed Freeze Problem of GUI when stopping recording with a lot of data

- MemoryToIceAdapter: put stopping of recording into its own thread and detached it to solve the problem of the GUI freezing if there is still data left to store after pressing stop
- Memory: Added information to print into log when storing of all data for this memory is finished
- BufferedMemoryMixin: removed unnecessary threading/parallelization and code that did not work (bufferFinished())