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

Remove code no longer needed

Remove duplicated code for checking groups and pairs in use

Rename forward and backward to the more appropriate positive and negative

Created new file for MuonDiff

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 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