v0.3.0

This is a breaking update that renames terminology and begins feature updates
based on experiences over the past year. Here's a summary of the terminology
changes:

1. Synthetic alarms are now called managed alarms since they are managed by
   Alarmist.
2. Alarmist.Definition is now Alarmist.Alarm to signify that you're
   defining alarms.
3. defalarm is now alarm_if. The way to read this is "[Alarmist] sets an
   alarm IF the following condition is true". Future releases will have other
   ways of indicating when alarms should be set.

When upgrading, you'll get compiler errors to guide you on the renames.

In addition to the above breaking changes, there are quite a few updates from
v0.2.2:

• New features

  • Support for tuple-based alarm IDs like {NetworkBroken, "eth0"} to allow
    for generic alarm types. The boolean logic for combining alarms supports
    variables now so that managed alarms don't need to know the
    instance-specific pieces until registration.
  • Support alarm severities. Alarm severities use the same atoms as Logger
    severities (:error, :warning, :info, etc.) and may be set on both
    managed and unmanaged alarms.
  • Add Alarmist.info/1 for quickly getting a list of set and cleared alarms
    when using the CLI
  • Support registering alarms and setting levels using the application
    environment via config :alarmist, ...

• Updates

  • Internally created alarms when registering managed alarms are now all
    :debug severity and won't display or be returned by default since most
    alarm querying functions return :info and higher. You can still get to
    them by passing level: :debug to affected functions.
  • Fix silent failures of Alarmist API calls immediately after Alarmist is
    started due to async gen_event handler registration. This seemed to only
    affect unit tests in practice.
  • Clean up state better when unregistering managed alarms and stopping the
    Alarmist app.
  • Many more unit tests for better code coverage of edge cases