Start a customstyle for bibliographic references

[mwtoews]

This PR follows on from #1041

Modifies reference label to use BibTeX key name, as it was last week. There is a check to ensure the BibTeX key name is just letters and numbers, for the RST link. Also, it's my preference to format names in References section with lastfirst, e.g. switch from "F. W. Bessel" to "Bessel, F. W." However, if anyone has a strong preference to keep it plain (as it is right now), I can do this before merge.

TODO (if we get there) is to modify the reference style to be more Harvard-like, with year after name(s). This looks to be much more work, but it could be put into bibstyle.py too, or potentially committed upstream to Pybtex.

Other misc. minor additions in this commit is to fix an uppercase title for an entry, and add a few more file types to .gitignore. The *.bak is from JabRef.

[kbevers]

There's a tab before return label which trips up my Python:

(base) C:\dev\proj\docs>make html
sphinx-build -b html -d build/doctrees   source build/html
Running Sphinx v1.6.6

Configuration error:
There is a syntax error in your configuration file: inconsistent use of tabs and spaces in indentation (bibstyle.py, line 51)
Did you change the syntax from 2.x to 3.x?
Makefile:56: recipe for target 'html' failed
make: *** [html] Error 1

[kbevers]

Also, it's my preference to format names in References section with lastfirst, e.g. switch from "F. W. Bessel" to "Bessel, F. W." However, if anyone has a strong preference to keep it plain (as it is right now), I can do this before merge.

+1 to this!

[mwtoews]

I've fixed up the white space error, and it looks set to merge now.

[kbevers]

Great. Thank you.