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.
First version of img2imgcoord and img2stdcoord
fixed typo
bugfix: for unknown reasons WarpUtils produced wrong command lines
bugfix: for unknown reasons WarpUtils produced wrong command lines (ii)
fix:docstring of traits.Directory was not correctly generated
changed use of os.unlink in favour of os.remove
correcting docstrings of the utils file
Merge branch 'master' into enh/FSLimg2coords

Conflicts:
	CHANGES
Merge pull request #888 from oesteban/enh/FSLimg2coords

FSL new interfaces: img2imgcoords and img2stdcoords
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
Merge pull request #906 from oesteban/bug/fnirtfileutils

Fix: fsl.WarpUtils
Merge branch 'master' into bug/fixEddyWrapper

Conflicts:
	nipype/interfaces/fsl/epi.py
fix typo
Merge pull request #907 from oesteban/bug/fnirtfileutils

fix typo in WarpUtils input traits
ENH: tidy up fsl-epi tools

* TOPUP: regarding #794, #796 I've cleaned up the docstring and implemented
  the three arguments that were still missing. The problem is that TOPUP
  admits one or more values for them, so the implementation of all the
  traits should be updated.

* Eddy: the implementation of @JensNRAD seems to work out, I reviewed
  the docstring. Close #769.

* Added deprecation notices and minor fixes.
pep8