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.
Merge branch 'master' into bug/fixEddyWrapper

Conflicts:
	nipype/interfaces/fsl/epi.py
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
Merge pull request #909 from oesteban/fix/TidyFSL-EPI

Tidy fsl epi interfaces