zbell plugin

This plugin prints a bell character when a command finishes if it has been
running for longer than a specified duration.

To use it, add zbell to the plugins array in your zshrc file:

plugins=(... zbell)

Settings

These settings need to be set in your zshrc file, before Oh My Zsh is sourced.

zbell_duration: duration in seconds after which to consider notifying
the end of a command. Default: 15 seconds.
zbell_ignore: if there are programs that you know run long that you
don't want to bell after, then add them to the zbell_ignore array.
By default, $EDITOR and $PAGER are ignored:
```
zbell_ignore=($EDITOR $PAGER)
```
zbell_use_notify_send: If set to true, notify-send tool is used -- if
available -- to display a popup on the screen. Default: true (enabled).

Adapted from an original version by Jean-Philippe Ouellet.
Made available under the ISC license.