SplitView for Pluma 1.20+
Based on
- Mike Doty's Gedit 2 plugin - http://www.psyguygames.com/SplitView2.tar.gz
- Maciej Zgadzaj port to (old) Pluma - https://github.com/maciejzgadzaj/split-view-pluma-plugin
TODO: Button "Another File" doesn't work. Variable results_view doesn't exist.