And so that it always wipes out all items.

The previous `show_delay` was incorrect.  It was changing the speed of the
transition, not the delay before the transition started.  I left
`show_delay` in there and mapped it to the (incorrect) `auto_hide_speed`
for backwards compatibility but removed reference to it from the README.

There's quite a bit of duplication among many of these functions.  I'm
going to add a few helper functions to clean some of it up.  It will make
adding new plugins easier as well as make the user experience more
consistent.  Not to mention cutting down on possible bugs.

This was much too prone to manual error.  For now I just went through the
commands that were predominantly 'defaults write' commands as that what
I'm currently the most focused on.

I also removed the duplication of the restarting of processes and made it
happen after any command (which has been given a value) has been run.

Apparently from having many contributors the docs got a bit out of date
(format-wise).  Some (most) of the "examples" were actually usage.

Examples should contain sample data.  Usage should contain placeholders.

Take the `service` plugin for example:

This is usage:

    m service load <service_name>

This is an example:

    m service load com.apple.sessionlogoutd

I didn't rewrite everything but I made some good progress.

Some places can't be replaced, but these could