Documentation Updates
Documentation Updates

Addresses a number of things:

- Uses "soft" newlines, so that test doesn't split weirdly due to newlines in the middle of sentences, etc.
- Lists out all of the error types, including the recently-added ones
- Adds note about wrapping handler functions in an Ember run loop

ember-cli/ember-ajax,manoharank/ember-ajax,manoharank/ember-ajax,ember-cli/ember-ajax,ember-cli/ember-ajax