v5.0.0

* Updated grid pattern that adds dynamic grids for more design flexibility.
* Renamed `.grid-img` to `.grid-dynamic`.
* Renamed several Sass variables for better semantics.
* Deprecated Slider and removed from add-ons. Linked directly to HTML5 Boilerplate version of `.htaccess` file.
* Updated `.screen-reader` class with more accessible HTML5 Boilerplate implementation. Added `.screen-reader-focusable` class.
* Removed general `*-space-*` classes in favor of `*-margin-*` and `*-padding-*` specific ones.
* Added `.list-inline` class.
* Removed `list-style` attribute from `ul` and `ol`. Let's browser defaults do their thing.
* Renamed `.group` to `.clearfix`.
* Added default `display: none` state to SVGs to prevent blank space from showing in unsupported browsers.