Firefox inner focus fix

Firefox adds 2px padding/border to a button element. when you have a
.button and a button element next to each other this shows. (button is
2px taller). resetting -moz-focus-inner fixes this
Update _settings.scss

add variable missing
removes empty commands and added new missing command
adds SCSS: how it w works section
removes empty commands and added new missing command
rechanging layout and adding new content
Update _buttons.scss

$button-border-color variable was not being utilized.
Update _settings.scss

adds the icon-bar settings
Update _settings.scss

Update grid/block_grid variable names to match their location in _settings.scss
Merge pull request #5346 from avr/patch-1

Update _settings.scss
Merge pull request #5340 from rlafranchi/patch-2

Update _buttons.scss
Add border color and hover color as params

per comment from pull request #5340
Fixed broken link

This is broken on the [published docs](http://foundation.zurb.com/docs/components/reveal.html) as well (under the section "Using the JavaScript").
Merge pull request #5353 from patik/patch-1

Fixed broken link in Reveal docs
Merge pull request #5349 from rlafranchi/patch-3

Add border color and hover color as params
Remove experimental variable and mixin
Delete _iconbar.scss
Add default value for inclusion variable in _icon-bar.scss
Typos in _settings.scss

Only some typos…
Update _buttons.scss

Fixes breaking change in #5439