using io.open

[cehbrecht]

Overview

This PR is updating PR #475 and uses io.open.

Related Issue / Discussion

475

Additional Information

https://stackoverflow.com/questions/40809901/python-2-7-io-open-use-from-io-import-open-or-io-open#40809945

Contribution Agreement

(as per https://github.com/geopython/pywps/blob/master/CONTRIBUTING.rst#contributions-and-licensing)

• [x] I'd like to contribute [feature X|bugfix Y|docs|something else] to PyWPS. I confirm that my contributions to PyWPS will be compatible with the PyWPS license guidelines at the time of contribution.
• [x] I have already previously agreed to the PyWPS Contributions and Licensing Guidelines

[coveralls]

Coverage remained the same at 74.05% when pulling d5939ca3ccb52981baa52554c4a09c55ad2ff05b on cehbrecht:update-pr-475-io-open into 5c52cd945a7a971e81ceee9a0ceb1d02b476fa5e on geopython:master.

[cehbrecht]

Looks like this approach leads into more PY2 compatibility troubles:

File "pywps/inout/basic.py", line 387, in file

    fh.write(self.data)

TypeError: write() argument 1 must be unicode, not str

[cehbrecht]

skipping this PR ... it becomes obsolete when using Python 3 only.