Make test requirements install normal requirements

This requires implementing the pip recursive requirements feature
in setup.py.
Fix README so that the example code runs
Indent and syntax highlight README code snippets
Add pip details to the top of the README
Merge pull request #15 from alphagov/bugfix-readme

Improve requirements installation and README
Add coverage and refactor test execution

- Use nosetests task rather than test as test support is deprecated,
  see;
  https://code.google.com/p/python-nose/issues/detail?id=219&can=1&q=with-doctest%20python%20setup.py%20test&colspec=ID%20Type%20Status%20Priority%20Stars%20Milestone%20Owner%20Summary
- Move nosetests flags into setup.cfg as per the docs, see;
  http://nose.readthedocs.org/en/latest/api/commands.html#nosetests-setuptools-command
- Switch on coverage and xunit output
Add coveralls support to travis build
Merge pull request #16 from alphagov/add-coveralls

Add coveralls
Explicitly install coveralls

The cli tool is needed which doesn't seem to get installed when relying
on setuptools test dependencies.
Add status badges for travis and coveralls
Merge pull request #17 from alphagov/add-coveralls

Explicitly install coveralls
Merge pull request #18 from alphagov/add-status-badges

Add status badges for travis and coveralls
Migrate dataset client into own module

We should be breaking up the functionality of the library into multiple
modules which are then aggregated in the performanceplatform.client
module. This is a common python style to limit the depth at which you
have to import.
Add AdminAPI client

Created an object which encapsulates a connection to the Admin API and
allows all requests required by Backdrop.