Review FSL eddy interface

Just fixed PEP8 errors in the interface and reviewed the solution
for the bugs, that were already solved.

Please, close #769.
fix:docstring of traits.Directory was not correctly generated
WIP: open new workflows group in dmri (preprocess)
Merge branch 'bug/AddIPythonLexer' into enh/NewEPIArtifactCorrections
enh:included eddy_correction
removed hardcoded tests
Merge branch 'master' into enh/NewEPIArtifactCorrections
enh:implementing new fmb workflow
add preprocessing utils
enh:new fmb_sdc workflow
enh:new fmb_sdc workflow
fix:doctests of new workflows
ENH:new preprocess interfaces in dipy (Denoise, Resample)
enh:new all-corrections workflows and example

When merged the new dipy interfaces I've written, this example should
be updated adding a denoising node.
multiple fixes and new features

* ApplyTopup is now called with correct arguments when the reversed
  encoding image is only one b0
* Added documentation
* Deprecated old workflows in nipype.workflows.dmri.fsl (added warnings in
  both documentation and code)
* Updated CHANGES
Merge branch 'master' into enh/NewEPIArtifactCorrections

Conflicts:
	CHANGES
Merge branch 'master' into fix/ElastixDocumentation

Conflicts:
	nipype/interfaces/elastix/base.py
fix:docstrings
Merge pull request #905 from oesteban/fix/ElastixDocumentation

Fix elastix documentation
Merge branch 'master' into bug/fnirtfileutils