Lofar-h5plot

**Updates**
* Do not reorder data again if solset or soltab hasn't changed after using the dropdown menus.
* Remove deprecated matplotlib calls.

**Bugfixes**
* Fix a bug where phases were not wrapped when plotting all stations.

**Updates**
* Add option to iterate over directions.

**Updates**
* Add option to plot all stations in case of waterfall plots.

**Bugfixes**
* Disable diffs when plotting weights.
* Don't keep the main window on top.
* Wrap diffs of phase quantities properly (fixes 22).
* Remove unused text that clashed with single-polarisation h5parms.

**Updates**
* Add option to plot weights.
* Add option to plot the forward difference along time and frequency axes.
* Add option to plot the XX-YY polarisation difference.
* Add a scrollbar for easier navigation.
* Plots now grow with window size.

**Bugfixes**
* Don't set flagged solutions to NaN (confusing for when solutions are actually NaN).

**Updates**
* Irregular h5parms with gaps between data are now padded when plotting waterfall plots. Irregularity is determined based on the first two time and frequency slots.
* Fixed a bug where switching between polarisation cleared the plot title.

**Updates**
* Plots adapt to the size of the window