Added "Cancel Operation" to the Progress Panel
Removed "Multiprocessing" QCheckBoxes from the GUI

Now multiprocessing is effectively always enabled.
Improved Cancellation and Removed Multiprocessing Baggage

- Cancellation works for both Importer and Analyzer
- After cancelling Importer, you have to re-open vis, because for some
  reason, it won't otherwise import correctly after cancellation
- Removed the "if multiprocessing" blocks in ___Thread.run()