Remove IJKtoRAS atrribute from Matlab image metadata

[cpinter]

When an image is loaded using the MatlabBridge, currently IJKtoRAS information is stored in two places:

• in img.ijkToLpsTransform
• in a field in img.metaData

The field in img.metaData is not used, just left there, so remove it, and just keep the img.ijkToLpsTransform (and make sure the field is created in the written file)

Maybe also add an example describing how to get the spacing from the img.ijkToLpsTransform (and a note that directions shall not be ignored and add an example for getting LPS from IJK and IJK from LPS).

Migrated from https://app.assembla.com/spaces/slicerrt/tickets/465-remove-ijktoras-atrribute-from-matlab-image-metadata/details