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   both very out of date.