don't seperate iterations of thinning and noise reduction.
Previously:
3 iterations thinning
3 iterations noise reduction

now:
3 iterations  of (first thinning then noise reduction)
Merge branch 'master' of https://github.com/JOSM/JOSM-areaselector

Conflicts:
	src/org/openstreetmap/josm/plugins/areaselector/ImageAnalyzer.java