double-barrelled filename support (but not HCP files :( )

This is now the new default behaviour when loading a new file

This change is not backwards compatible!

Image.save was resulting in a Nifti without a header.

There were some subtle bugs in the use of get_all, which should now be fixed. They were caused by having multiple optional variables and the result not being deterministic if these were iterated in different orders.

sure the MGHImage class preserves this.

nibabel

usage docs.

affine.rescale function, for reuse.

methoed to do this which is both fast and foolproof

directory check to be skipped

auto-load any JSON files that sre found. Fix to bids.isBIDSFile