fix errors in new sphinx version

[kain88-de]

Changes made in this Pull Request:

• cite reference Seyler2015b to fix sphinx build.

PR Checklist

- [ ] Tests?

• Docs?
  - [ ] CHANGELOG updated?
  - [ ] Issue raised/referenced?

[kain88-de]

Turns out there are more reference issues. I assume this is due to a sphinx update. I managed to fix some but I don't know why there is an error in encore.rst about missing dereferences.

[kain88-de]

See sphinx-doc/sphinx#3565

[orbeckst]

This is fixed in PR #1126 – I think we will be able to close this PR after merging #1126

[kain88-de]

@orbeckst can this be closed then? Do you know about the current error I'm getting?

[orbeckst]

I didn't know about any false warnings in sphinx. I just got the failures due to citations and made sure that everything is referenced. In particular, I remember looking at the encore docs and wondering why it didn't work. I think I worked around it in 8cd7603 by just renaming the reference... weird. I made the same changes in references that you have here.

PR #1126 builds fine with sphinx 1.6.1 and warnings as errors so I am pretty sure this PR can be closed.

I will do so and we can re-open if necessary.