Stacking <button>'s

`<button>`'s won't get expanded to full width if stacked (orientation == vertical).
Same spacing between links in top bar

Changing the value of $topbar-link-padding will change the padding between links, but not between e.g. buttons.
Fixed header-font-style value
zurb/foundation#6109 - change split regexp to handle urls with parenthesis
Added ability to customize split button pip
updates all js docs pages with reflow info
Fix broken back button in tabs with deep linking

This change fixes a bug in tabs which have deep linking enabled, whereby
the user, in using the browser back button, would only be able to
navigate backwards as far as the default tab hash location. Attempting
to navigate back to the previous page would result in infinite
redirection back to the default tab. For moreinformation see [this
issue](https://github.com/zurb/foundation/issues/6102)

This change has the tab control remember the entry location upon
initialization, and then whenever the hash changes, it compares the
current location.hash value with the entry location and the default hash
value, in order to determine whether to update the location.hash or
simply allow the navigation to occur without modifying the
location.hash.
Merge pull request #6103 from wolfgang-demeter/patch-3

Stacking <button>'s
fixes type in the collapse/uncollapse rows example, resolves #6124
adds notes on accordion docs about new markup
Merge pull request #6126 from janoskk/fix-6124

fixes type in the collapse/uncollapse rows example, resolves #6124
fixes grid collapse example
fixes grid collapse example
Merge pull request #6118 from michaelbromley/deep-linked-tabs-fix

Fix broken back button in tabs with deep linking
Merge pull request #6115 from DrSammyD/customize-split-button-pip

Added ability to customize split button pip
fixes visability class on docs example for grid collapse
Merge pull request #6108 from kostaspt/patch-2

Fixed $header-font-style value
Merge pull request #6107 from kostaspt/patch-1

Same spacing between links in top bar
complete audit of settings file vs scss variables
removes extra comment marks from settings file