* build docs through tox environment
* build docs on travis. Travis build checks that we haven't broken docs which would get pushed to rtd
* generate docs directly from repo markdown using recommonmark, rather than converting into new files with pandoc
* unpin recommonmark version
* remove redundant makefiles, rely on tox to do our docs building (we don't really reliably support anything bar html/json generation anyway)
* remove redundant conda `docs/environment.yml`
* fix docs version using `.bumpversion.cfg`
* update docs readme
Josh Barnes