Allow default value for block grid alignment

Adds block grid alignment setting to _settings.scss, for consistency
with other block grid variables.
Limit legacy visibility classes to legacy breakpoints

When enabled, generating legacy visibility classes only uses small,
medium, and large breakpoints. Since those were the only breakpoints
that existed in Foundation 4, there is no need to generate visibility
classes for any breakpoints beyond those three.
orbit should call start on timer restart event
Merge branch 'master' of github.com:zurb/foundation
don't require orbit links to be anchor tags
Makes me feel dirty, but this does solve a specificity / conflict issue
Added range slider variables to settings
Merge pull request #4622 from NikhilKalige/range-slider-variables

Added range slider variables to settings
Fix Duble scroll if using Pizza Pie

If pizza pie uzing in last row. Then appears double scroll.
Allows first shown image to be configured in markup
Fixes to docs
Fix captions in Clearing viewer
Fixed the flex-video class for vimeo embeds
Fixing Forms in Tabs width issue
enable orbit vertical scrolling unless horizontal scrolling has crossed 5px threshold
derive pre- and postfix height from input
Extraneous line in foundation.scss file

I notice that there's this line at the end of scss/foundation.scss:

  // * { border-radius: 500px !important; }

It was introduced in this changeset:

https://github.com/zurb/foundation/blob/09028fdb8abb171672de760d3173402a76ace32d/scss/foundation.scss#L47

It's a comment and seems like something extraneous that got into the commit by accident, especially considering this file is one that could be replicated by downstream users to include only certain components.
Merge pull request #4561 from serglo/patch-1

Set <hr> margin difference to use rem-calc
Update deep linking documentation.
Trigger handler on tab content as well as tabs.