#1 Border agreements are not persistent

[Chris Shaffer]

If a planet name that is part of a border agreement
changes, the border agreement no longer displays on the
map or in the border agreements tool, but it is still
present in turn.borders.gvi. The border does still display
when viewing turns prior to the planet name change.
Any edits using the border agreements tool erases the
'broken' border from turn.borders.gvi.

Current workaround is to hand-edit turn.borders.gvi.