Instead of echoing and error, just echo a message about mplayer not
being installed. Errors look pretty annoying on initial load, and I
don't think this is worth the red background colour. It could be that a
user has two machines, one with mplayer installed and one without. In
that case, I don't want people to have to disable the plugin on one
machine. That seems like too much to ask.

I think this is a nice middle-ground between alerting users that
something is needed by the plugin and not barfing if it's not there.

On plugin load, if mplayer isn't installed then fail ungracefully. Since
we depend on mplayer in order to play any sounds, my thinking now is
that I want to fail immediately.

Still trying to decide if this is be best course of action. Maybe I just
want an informative message instead of a complete failure.

Clean up functions, move everything into autoload/, move code around a
little bit.

Add a command-mode command to toggle insert mode sounds between normal
and Galaxy Far Far Away versions.

Add commented mappings that I've been trying to get working but that for
one reason or another haven't been able to figure out how to do so.

Without this, the audio files wouldn't be able to play unless you were
cd'ed into the script's root directory. We want them to play no matter
where your pwd is.

Use the Jump sound for sentence & paragraph movement.

Add Jump sound mappings for:
* gg
* G
* <C-i>
* <C-o>

In addition to the regular search commands, add the search by word ones.