Bug#832578: cpl-plugin-visir: does not work with packaged swarp

[Julian Taylor]

I agree that the patches should be more easily extractable, this was 
originally planned but time constrains did not allow this for the last 
two releases, hopefully next time the changes will be included as 
separate patch files.

The patches are for the most part incomplete and not upstreamable as 
they fix the bugs only for the configuration used by visir or add a 
feature only in points visir needs it. There has not been time to 
generalize and test them for the many ways swarp can be used. The last 
time this was done it was promptly broken again in the next code dump so 
motivation is low to do so again.