Lofar-h5plot

Release to get a Zenodo DOI.

**Bugfixes**

* Use a refrence antenna when plotting TEC solutions.

**Bugfixes**
* TEC soltabs for real now.

**Updates**
* Support for multiple directions inside an H5Parm.
* Phases are always wrapped, so checkbox removed.

**Bugfixes**
* TEC soltabs better supported.

**Updates**
* Singularity recipe and container now available.

**Bugfixes**
* RMextract plotting was broken.

**General notes**

**Updates**
* Iterate through time and frequency (if applicable) with buttons.
* Support changing station lists between solsets/soltabs.

**Bugfixes**
* Load the first solset rather than `sol000` specifically.

**General notes**
* More documentation for classes/functions.
* Start separating plotting logic from the rest, so things are less intertwined.