Post-Basic-Features: Allow temporary caching of encounters / loading existing encounters

[Shiniri]

Putting this here so I can hold myself accountable. It would be interesting to expand the parser so it is able to open existing encounters, so that it is possible to edit them with this app once they are created. It would also be nice to be able to save encounters, so that one
can pause editing and pick it up again before the encounter is finished completely.