The status bar at the bottom of the GUI is now populated with the
currently loaded calibration.

Removes all of the from __future__ imports that open and close the
brackets on the same line. This is most of them.

Co-Authored-By: StephenSmith25 <56431339+StephenSmith25@users.noreply.github.com>

Needed to add checks around makedirs(), throws an error if the directory
already exists.

Also updated class_maker.py

Fixes all flake8 3.7.9 warnings as part of the Python 2->3 transition.

If the table was repopulated at any time, any plotted workspaces would
be added to the plot every time the table was updated. Resulting in
extra lines shown on the legend that couldn't be seen on the plot.

Should have fixed these as I went along, but I'm not sure where they
failed to fixup the commits. Most were introduced as a result of
handling the checking of the plot box when repopulating the table.

Observer pattern uses has the data widget as an observable that sends
the plotting widget the workspaces to add or remove from the plot when
the 3rd column in the table is ticked and unticked respectively. The
pattern also handles the removal of indiviual workspaces or the
clearing of all tracked workspaces.