Decide on metadata schema

[patricksnape]

Metadata should come in two forms:

• Optional metadata - probably in the form of a dictionary
  • description
  • publications
  • any other notes
• Mandatory metadata
  • 'Pretty' name
  • Supported platforms - {win32, win64, linux32, linux64, osx64, all}

These should be used in conjunction with the yaml for validating an experiment.

[jabooth]

The metadata framework has largely been implemented as of 444290a, but now we need to get a feel for what keys we actually need and set the schema appropriately.