"T1w.json" is a valid sidecar file

metadata file name, as files within a BIDS data set may be sym-linked from
another file/directory structure (e.g. datalad/git-annex)

fslpy for the most part, so are being moved to fsleyes-widgets

atexit (settings)

queued task raises an error.

Without this any FSL call under Windows opens potentially multiple
transient console windows which is distracting and slows down
performance

correctly prepended.

also added verbose option and finally some tests

qstat should not be called regularly