Add media query mixins
Remove some duplication of row/column resets for mobile
Add vertical margin to reset columns
Add "breakout" columns
Add a fix for IE 10 Snap Mode
Add fluid img styles
Add responsive visibility helpers
Merge branch 'development' of github.com:whoisartifex/shelves into development

Conflicts:
	scss/shelves/_variables.scss
	scss/shelves/mixins/_base.scss
	scss/shelves/mixins/_generators.scss