Update man page generation process

* Update makefile to place man pages in the expected location
* Update .gitignore with a few autogenerated helper files created
  during man page generation.
* Updated requirements.txt to use docutils 0.9.1.  There's a bug
  in 0.10 of docutils that causes man page generation to fail.

  See:
https://bitbucket.org/birkenfeld/sphinx/issue/998/docutils-010-will-break-sphinx-manpage
Merge branch 'manpage-build' into develop

* manpage-build:
  Update man page generation process