Code, comments and README.md give inconsistent accounts of available notification types

[colonelpanic8]

The code comments list the following types of notification

;;   message   - Uses the Emacs `message' facility
;;   log       - Logs the alert text to *Alerts*, with a timestamp
;;   ignore    - Ignores the alert entirely
;;   fringe    - Changes the current frame's fringe background color
;;   growl     - Uses Growl on OS X, if growlnotify is on the PATH
;;   libnotify - Uses libnotify if notify-send is on the PATH
;;   notifier  - Uses terminal-notifier on OS X, if it is on the PATH

While README.md lists these types:

| message       | Uses the Emacs `message` facility                                 |
| log           | Logs the alert text to *Alerts*, with a timestamp                 |
| ignore        | Ignores the alert entirely                                        |
| fringe        | Changes the current frame's fringe background color               |
| growl         | Uses Growl on OS X, if growlnotify is on the PATH                 |
| gntp          | Uses gntp, it requires [gntp.el](https://github.com/tekai/gntp.el)|
| notifications | Uses notifications library via D-Bus                              |

while (mapcar 'car alert-styles) yields:

(fringe gntp growl ignore ignore libnotify log message notifications notifier toaster)

[jwiegley]

I believe they evolved at different times.