Update _block-grid.scss

fix issue display list-style option
Reducing verbosity of comments, fixed a typo Line 551, adjusted the spacing before each setting so the document is easier to scan.
Added glowing effect option for inputs
Merge branch 'master' of https://github.com/zurb/foundation
Added glowing effect mixin
Fix order of operation when calculating margin for forms in rows
Fix #2220 - Documentation change for top bar

Added mention of section class="top-bar-section" to documentation, which
seems to be a new requirement for Foundation 4's top bar
Matched reveal sizes to reflect documentation
fix column float for rtl (noted: $default-float == right when $text-direction == rtl)
Merge branch 'master' of https://github.com/zurb/foundation
Added glowing effect variables in documentation
Merge pull request #2234 from blai/master

Fix column float for rtl
Merge pull request #2233 from skord/master

Reveal sizing classes don't reflect the docs
Merge pull request #2229 from mhchen/update-top-bar-docs

Fix #2220 - Documentation change for top bar
Merge pull request #2227 from sagamore/form-row-margin-fix

Fix order of operation when calculating margin for forms in rows
Merge pull request #2207 from Rodsevich/master

Added block-glowing-effect mixin and glowing effect for form's inputs
fixed arrow alignment on dropdowns in the desktop view of the topbar
Merge branch 'patch-1' of git://github.com/ngoduybien/foundation into ngoduybien-patch-1
updated block-grid
made some updates to the styling of comments in the variables file