First major release

This is still a pre-release, but there are some really big changes that make it appropriate to add a major version number.

• Units
  • Units are no longer typed. You can check if a value has a specific unit with the MetricValue.unit property.
  • Units are now required for many functions, such as periodic.
  • New utility function, from, allows you to convert a value and get it as a Double in the same step.
• Subsystems
  • Subsystems now need to be wrapped in a Worker using the add function.
  • Subsystems have the methods default and setup that can be overridden.
• Other small tweaks and changes