stdout/stderr streams go.

gives $FSLDEVDIR precedence, and also allows a global override.

stdout/stderr, and also redirects it to real stdout/stderr.

get image data as numpy array.

Support fsl data image in wrappers

See merge request fsl/fslpy!53

More label atlas bug fixes

See merge request fsl/fslpy!52

AtlasDescription.labels list.

Updates to atlases

See merge request fsl/fslpy!51

    - not all atlases have a 2mm version
    - label atlas value does not correspond to its index in the
      AtlasDescription.labels list.

Enh/skip unchanged invalidate

See merge request fsl/fslpy!50

Added support for submitting functions from __main__ script

See merge request fsl/fslpy!49

fixed a small documentation error as well
added a warning about missing if __name__ == '__main__' guard in script

Fix issue with callfsl unit tests, causing other tests to fail.

See merge request fsl/fslpy!48