Merge pull request #28 from dohmatob/packaging

Packaging
This PR features:
- pypreprocess is now a package (in `setup.py` sense)
- fixes for some serious issues
- pure-python code for slice-timing correction, motion correction, coregistration, and smoothing (see README.rst)
removed ghost file
Merge branch 'master' of http://github.com/neurospin/pypreprocess into packaging