Make names of  UI code pep8 compliant

See merge request !13

Shorten all lines to 80 characters.

Remove commented code in calendar_dialog.py, channel_prefer_dialog.py,
mainwindow.py, time_power_squareddialog.py, and db_gui_superclass.py.

Change name of waveformdialog.py and plottingWidget.py to use snake_case.
Change a name in time_power_squareddialog.py to snake_case.

Make names in time_power_squareddialog.py and waveformdialog.py use
snake_case.

Make names in plottingWidget.py use snake_case.

Rename channeldialog.py, channelpreferdialog.py, dataTypedialog.py,
dbgui_superclass.py, paramdialog.py, and plottypedialog.py to use
snake_case
Rename variables and functions in above files to use snake_case

Rename calendarwidget.py to calendar_widget.py
Rename variables and functions in calendar_widget.py to snake_case

Ruler and zoom in TPS

See merge request !11

Time-power-square

See merge request !7

Plotting

See merge request passoft/sohstationviewer!6

Read and plot RT130

See merge request passoft/sohstationviewer!5

Read mseed and log data

See merge request passoft/sohstationviewer!4

Main UI and miscellaneous associated widgets

See merge request passoft/sohstationviewer!3

Gitlab CI pipeline and setup files

See merge request passoft/sohstationviewer!2