DOC : Major work to FAQ pages and devel guide

closes #3115
closes #2198

 - strengthen suggestion to use auto pep8 checker
 - added example  minimal numpydoc docstring
 - formatting
 - tweaked suggested imports to make copy-paste easier
 - updated list of versions of python
 - github PR as primary mode of communication
 - Added map of major parts of a figure
 - removed reference to pythonbrew (which has been deprecated)
 - moved tox section to very end as the docs and the tox file are
   both very out of date.
Merge branch 'v1.4.x'

Picks up edits to the FAQ and devel guide.