Four-channel image handling in MahalSensor corrected
Four-channel image handling in MahalSensor corrected

  * fox-toolkit 1.0 used to load RGB as 3-channel images.
    now, all color images also have constant alpha at 255
  * bugfix is to always ignore alpha channel
  * antmodel/ant.brain now finds sub-shapes

git-steb/structural-deformable-models,git-steb/structural-deformable-models,git-steb/structural-deformable-models