Fixes #3848: makes modal bg show/hide when swap style.

If one modal step is followed by a default style step, modal background
is hidden and if a default style step is followed by a modal step, the
modal background is shown.
Avoid to show joyride modal before needed.

This way, is up to the settings how the joyride modal will be shown
(with a simple show method or a fade effect).
Use fadeOut to hide joyride modal bg according to settings.
Active state styling

Actually makes use of the $icon-bar-active-color variable to set the
background when an "active" class is added to the anchor, akin to what
happens with the :hover pseudoclass.
Update foundation.clearing.js
Update foundation.dropdown.js
Update foundation.joyride.js
Update foundation.js
Update foundation.magellan.js
Update foundation.offcanvas.js
Update foundation.orbit.js
Update foundation.tab.js
Update foundation.topbar.js
adds even class to docs and various fixes to buttons and button groups
Merge pull request #6022 from enyce12/master

Consistent quotes across js files
fix(js): consider 0 value for `pageX`, `pageY`

* remove error message `Uncaught TypeError: Cannot read property '0' of
undefined` if mouse position X/Y is 0
* add `get_cursor_position(e, xy)` method

If you start dragging the slider and move the mouse position X/Y until
it is `0`, it is counted as falsey which means `||` in [line
49](https://github.com/zurb/foundation/blob/master/js/foundation/foundat
ion.slider.js#L49) and in [line
55](https://github.com/zurb/foundation/blob/master/js/foundation/foundat
ion.slider.js#L55) keeps going until it gets to
`e.originalEvent.touches[0].clientX/Y` where it raises an error if it
is no touch device. I changed it to explicitly checking that the values
are `undefined`.
Properly extending dropdown library
Removing -webkit prefixe for border-radius

The prefix is only needed for Safari 4, which is such a fraction of
usage.
See: http://css-tricks.com/do-we-need-box-shadow-prefixes/
http://caniuse.com/#feat=border-radius
Merge pull request #6025 from andreruffert/fix-pageXY-slider-js

fix(foundation.slider.js): consider 0 value for `pageX/Y`
Merge pull request #6029 from zurb/dropdown-callback-bug

Properly extending dropdown library