Rasterizer is HDF5able
Merge pull request #437 from jabooth/rasterizerimprovements

GLRasterizer becomes HDF5able
adds extract_channels method to Image
remove accidental import
Merge pull request #438 from jabooth/extract_channels

extract_channels
Make the LSJON importing ordered
Make the LJSON import use PointGraph

Create a pointgraph if there is valid connectivity
information
Reorder the labels

Keep the order stable so that PTS to LJSON and back works
properly. The order MUST be maintained to make sure that the
underlying pointcloud maps back and forth
Update landmark.py
Update landmark.py
Merge pull request #439 from patricksnape/labelling_fixes

Labelling fixes
Merge remote-tracking branch 'origin/master' into advanced_widgets