pep8 code style checking for python about esmvaltool

[bjlittle]

@mattiarighi I'm slightly confused (a normal state of being for me these days) ... but why is there pep8 source code being held within this repo? 😕

Surely, this should be purged in favour of pulling in 3rd party code as part of the required ESMValTool conda requirements? For example, see https://pypi.python.org/pypi/pep8/1.7.0 and also https://github.com/conda-forge/pep8-feedstock ...

I'm 👎 for https://github.com/ESMValGroup/ESMValTool/tree/master/util/pep8-checker

[bjlittle]

@cehbrecht 👍 I agree. We should enforce PEP8 compliance and have a PEP8 unit test that checks the code base in the chosen CI framework (i.e. travis) triggered by PR by users or devs.

[mattiarighi]

There is pep8 checker available in the tool at:
https://github.com/ESMValGroup/ESMValTool/tree/master/util/pep8-checker

@ESMValGroup/esmvaltool-coreteam

[mattiarighi]

@bjlittle The pep8 checker was introduced by Martin long ago, I really don't know the reasons for that.
If there is a better solution I'm fine with it, as long as we can keep a coding standard.
This should also apply to NCL: as far as I know there are no rules for that, and Martin introduced a very basic ncl-checker https://github.com/ESMValGroup/ESMValTool/tree/master/util/ncl-checker, but it needs to be improved.

@ESMValGroup/esmvaltool-coreteam

[bjlittle]

@cehbrecht also see #34

[bjlittle]

Closed by #39