FYI new plugin RelationDissolve

[John Kennedy]

Greetings.
FYI I have written a small plugin to help dissolve relations. More info
below. If you think it is appropriate functionality to integrate into core
let me know if you want me to give it a shot.

Keep up the great work,
 - John

Main intent is to make it much easier to create boundaries that are derived
from existing smaller boundaries in OSM. Documentation here:
https://wiki.openstreetmap.org/wiki/JOSM/Plugins/RelationDissolve.

I tried writing for simplicity of integration and maintenance rather than
performance, as per your dev guide.

Key logic is only ~4 lines in:
https://github.com/jkennedyie/relationdissolve/blob/master/src/org/openstreetmap/josm/plugins/relationdissolve/actions/RelationDissolveAction.java