Add a button to unlink PixelGeom.
Also deselect the PixelGeoms when they have been characterized.
Merge branch 'dev' of https://github.com/Mendroyxx/FeatureApp.git into urbapp_last
Reduce the size of the buttons is CharacteristicsFragment.
Move the attribute selected and linkedPixelGeom from PixelGeom to Element to make it more logical and avoid issues when editing the PixelGeom of a (weak-)linked Element.
Merge pull request #89 from jparty/urbapp_last

Add a button to unlink PixelGeom.