#1 Use JSON instead of YAML

We should use JSON instead of YAML for configuration and other data. Rationale for this decision are as follows:

• Either one would work just fine for this application
• Python has a built-in JSON library
• YAML is an external dependency
• We currently have extra code so things don’t break if our YAML decoder isn’t available
• Most importantly, I just like JSON

YAML has been removed and replaced with JSON. There is, however, a problem with conflict resolution between command-line arguments and the configuration file. Once this is fixed, I will close the issue.

Configuration/argument behaviour fixed: see 87c0a1bfe9 for more details.