py2/3 compatibility

length 1

the fsl namespace in other projects. This breaks python 2 support, but can be
fixed by touching fsl/__init__.py

Master

See merge request !32

convinced that this is foolproof, but it seems to work.

method.

different shapes

everywhere.

it accepts numpy arrays

Floating point numbers are good for nothing

See merge request !31

Unit tests

See merge request !30

accept rotation matrix

Post-release version bump

See merge request !29