Brainweb

- update documentation
- add `volshow()`:`vmins`, `vmaxs`, `tight_layout`

- expose `get_files():progress=True`
- add CI testing (travis)
+ add `flake8`
+ add `setup.py check`
- move to `setup.cfg`
- add & update badges

Beta release

Features

- Caches data to `~/.brainweb/`
+ raw data source <http://brainweb.bic.mni.mcgill.ca/brainweb/anatomic_normal_20.html> `uint16(362, 434, 362)`
- Transforms to Siemens Biograph mMR volume dimensions `float32(127, 344, 344)`
- Modifies to have FDG, T1, T2 and attenuation map intensities
- Adds non-piecewise-constant randomised structure for more realistic ground truths
- Adds lesions
- Flexible multi-volume slicing tool for Jupyter notebooks `brainweb.volshow`