Sticky menu height protection and topbar breakpoint

[vita10gy]

Add protection so a menu won't be sticky if it's taller than the screen (generally, once opened).

Otherwise you're never able to get to the end items.

I've also added the topbar breakpoint option (which seems like the most
likely one a person really means) and cleaned the function up to use the
existing small() medium(), and large() functions it was already half
using.

Addresses issue #6631

[vita10gy]

It would be a non backwards compatible change, but I think it aught to be considered for a future version that sticky_on take in arbitrary queries (small-up, medium-only, large), and work like the standard queries already do. Great pains now are taken to ensure small means "small only" medium means "medium only", etc, even though this is generally the opposite of what is meant.

Basically sticky_on:[foo,bar] should check
matchMedia(Foundation.media_queries['foo']) or
matchMedia(Foundation.media_queries['bar'])

[zurbchris]

At this time, we aren't adding any large features or changes that may affect current usability. We are, however, working hard on Foundation 6, and will keep this in mind. Thanks for contributing!

[vita10gy]

I'd file this as more of a bug fix than a "feature". Currently a menu is made sticky even if it's taller than the current window, meaning you can't ever get to the bottom of the menu.

This check makes it so it only applies the sticky if a sticky would fit, otherwise it would scroll as a normal in place menu so you can get to the "missing" options.