Updated the loadmuonnexus1 loader to read period information. Created a new widget for the period information. Need to deal with what happens when information cannot be found

Added highlighting from xml file for diffs

Rename forward and backward to the more appropriate positive and negative

Grouping description to empty

Remove some changes as they are fixed in a separate PR

Description on grouping tab better with no data loaded

These additional notifiers were added to ensure that the plot cleared correctly. This led to crashes on instrument change however. As the the plot updates naturally and correctly when you add data back in I've undone this change as it caused more problems than it solved.

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

Also updated class_maker.py

The pairing table wasn't updating correctly if an incompatible pair was entered into the table.

The tests have been updated based on the new columns present in both tables
Fixing failing tests
Correcting flake8 warning

The multi-period widget was removed from the GUI when the home grouping widget was removed. This has now been added back in.

Based on the feedback from a scientist the home tab group widget is being removed.
Plotting is now controlled in the grouping tab

The tables in the grouping table now have analyse column, which decides whether the group or pair will be plotted.
Adding option 'tiled by'

This enables the plots to be tiled by run or group/pair

Plot will now auto update its layout on resize

Fitting tab is updated to abide by the groups and pairs selected in the grouping tab

Tiled plotting scales to the same axis

Separating dock widget into its own file such that the window layout will update when the window is docked and undocked

The observer pattern is not Muon specific and could be used elsewhere. Moving it to somewhere not related to the muon GUI reduces the chance of the code being duplicated.

tests started as well.