Replace growl alert library

The previous growlAlert library limited the clarity of feedback
provided to users by alerts in several ways:

  - Messages queued one at time, leading to confusion about what action
    an alert is responding to if multiple alerts created cumulative
    delay.
  - The same color for all alerts equivocates action confirmation,
    warning, and error notification. When performing tasks routinely
    generating notification alerts, such as reviewing, users can
    desensitize to alerts and inadvertently ignore warnings.
  - The library provided no easy way to mitigate either of the above
    issues, even through callbacks.

BlockUI has a primitive growl alert functionality, but it has similar
limitations.

Replace the growlAlert library with jQuery growl, which is of similar
size but has desktop growl-like stacking alert queues and supports alert
styling. Match alert titles to contextually style most existing alerts.
Replace legacy direct calls to the growlAlert library with calls to the
more commonly used `growlAlert` global helper.
Improve several alert messages (minor)