[#1180] Raise 404 for org or group if called wrong

Raise a 404 if a group is called by organization_show
and vice versa.
[#1211] Add exception guidelines to Python coding standards
Add logging example to Python coding standards
Correct some Sphinx formatting
Correct some grammar.
Fix the title styles in a docs file
Add docstring guidelines for cross-referencing code objects
Remove formatting cleanups stuff from coding standards

This coding standard was wrong
Reorder some docs subsections
Docs: add a bullet-point
Add a cross-ref in the docs
[#1180] Add tests
Correct syntax
[#1180] Change typos and get the tests to pass
[#1180] *Really* fix tests
Merge pull request #1189 from okfn/1180-groups-orgs-404

[#1180] Raise 404 for org or group if called wrong
[#1211] Correct a typo
Merge pull request #1211 from okfn/1211-add-exception-guidelines

Add exception guidelines to Python coding standards
[#943] Autodoc the plugins toolkit

ckan.plugins.toolkit isn't compatible with autodoc. Autodoc supports
modules and classes, but the plugins toolkit is actually an
object-instance masquerading as a module.

Added a Sphinx extension to do what autodoc does for classes and
modules, but for the plugins toolkit object.

Added a custom __dir__() method to the plugins toolkit so that
inspect.getmembers() works as desired for it.
[#943] Add some docstrings to lib/base.py

These are functions that are imported into the plugins toolkit, so they
need docstrings.