Refactoring
- Replaced _grid.scss logic with a couple breakpoints loops
- Moved $grid-selector-types from global space to parameter of “grid-selectors” mixin. (Also added)
- Rewrote “columns” and “blocks” mixins to take a list (intentionally mirroring $breakpoints definition format) and use a breakpoints loop.

Specific changes
- In scss/layout/_grid.scss
- - Moved adapter block mixin to mixin “grid-adapters” under “grid-selectors”
- - Removed use (not definition) of collapse mixin. Sadly I couldn’t grok how to make that work with a mobile first approach.
- - Note: Changes are pretty much contiguous.
- In scss/core/mixins/_layout.scss
- - (Moved adapter block mixin here)
- - Added nth-child clear resets on columns and blocks
- - In grid-selectors mixin
- - - Made sure to set $target to ‘’ if false. Bools apparently are concatenated like strings (+ false becomes + ‘false’)
- - - Added placeholder for column definition. Reasoning being that whether or not the mixin is called outside a media query cannot be accurately determined, and redefining floats for each column is wasteful. Placeholder is intended only for internal use only.

Notes
- This failed some of the tests because of change to mixin parameters (columns, blocks), included tests for perusal.