Bug#705548: josm: backport josm

[Sebastiaan Couwenberg]

Control: tags -1 pending

Now that the embedded metadata-extractor is used, packporting josm has
less impact.

No newer version of libmetadata-extractor-java is required for josm now,
which would break its other reverse dependencies (gpsprune & tika).

Backporting josm requires backporting jmapviewer, which breaks freeplane.

Until freeplane is backported, the jmapviewer backports and freeplane
from stable won't be co-installable.

Kind Regards,

Bas