Fixes TypeError bug when you have only one dash

If the current dash happens to be the next dash, the iframe was
removed before the dashthe dash was sent on to be displayed again,
causing a TypeError when the .display method referred to the .iframe
property.

If you have a single dashboard, when testing for instance... this bug
was made evident.
Adds 'between' option, displays dash certain hours

If the option is set on the next dash, and the current time is outside
of the hours specified in 'between', then the dash is skipped and the
same test is conducted on the next dash.
Simplify css application

This is a breaking change.  By changing the configuration format of the
css properties, we can apply them directly using jQuery.  No need to
iterate over them.
Add 'cleanupCb' opt, allows programmatic cleanup

By adding a callback to the dash config, per-instance page manipulation
and programmatic css application can be done.  This allows for some more
creative dashboards.
Added bus stop example

Highlights new 'between' and 'cleanupCb' options.