Review Card Client defaults and documentation

Closes #47 (closed)

Update README with:

• Installation pre-requisistes.
• 'Standard' installation labelled as such. (I'm not 100% happy with recommending an install to python's site-wide packages, but personally feel like recommending a virtual environment is asking for trouble. Suggest we leave instructions as a site-wide install, and users who understand python will be able to work it out on their own. If they don't really need python for anything but this, a site-wide install won't hurt them.)
• Removed $ from bash commands, some users will be on windows so may cause confusion.
• Add notes on:
  • Importance of configuration.
  • Example configurations found in example-configuration directory.
  • What the card states are and what they mean, plus recommended filter option for most use-cases (get all the issued cards).

Update config.example.yml with:

• Change deprecated params to filter.
• Add comments in the queries section to further explain each query.