[ENH] Improved PEP8 Compliance for interfaces/fsl

[mgclark]

This PR improves the PEP8 compliance of interfaces/fsl and is a partial fix for Issue #597.

The initial PR includes the following:

File             Violations    Reduction   Remain
-------------------------------------------------
base.py          1             1   (100%)  0 
dti.py           162           162 (100%)  0
epi.py           18            18  (100%)  0
maths.py         36            34  (94%)   2
model.py         104           97  (93%)   7
preprocess.py    128           116 (91%)   12
utils.py         134           117 (87%)   17 

TOTALS --------- 583 --------- 545 (93%) - 38 ---

There are still some long docstring lines; wrapping them made CircleCI unhappy. Even with those outstanding, the readability of the code has been improved.

[coveralls]

Coverage decreased (-2.6%) to 69.695% when pulling 152f461 on mgclark:pep8/fsl into da1f544 on nipy:master.

[oesteban]

Hi @mgclark, I'm playing around with the docker images running tests in circleCI, that's why your tests are failing here. I'll try to find a solution for this ASAP

Sorry about that.

[mgclark]

@oesteban No problem! Thanks!

[coveralls]

Coverage increased (+0.006%) to 72.269% when pulling 2566e12 on mgclark:pep8/fsl into da1f544 on nipy:master.

[oesteban]

Hi @mgclark, could you merge with current master? If you don't have the upstream set, you could do the following in your nipype's git root:

git remote add upstream https://github.com/nipy/nipype.git
git fetch upstream
git checkout pep8/fsl
git merge upstream/master

I don't think you will have any conflicts. If so you'll need to fix them, I will assist you with that. Once everything is merged and committed, you just need to do git push.

[mgclark]

@oesteban No conflicts -- thanks!

[coveralls]

Coverage remained the same at 72.261% when pulling 8366201 on mgclark:pep8/fsl into b05d153 on nipy:master.

[coveralls]

Coverage remained the same at 72.261% when pulling 8366201 on mgclark:pep8/fsl into b05d153 on nipy:master.

[coveralls]

Coverage remained the same at 72.261% when pulling 8366201 on mgclark:pep8/fsl into b05d153 on nipy:master.

[coveralls]

Coverage remained the same at 72.261% when pulling 8366201 on mgclark:pep8/fsl into b05d153 on nipy:master.

[coveralls]

Coverage remained the same at 72.269% when pulling 29311ae on mgclark:pep8/fsl into 99d191a on nipy:master.

[mgclark]

Tests are passing -- this should be ready to go now.