Revert "Fluid images, mobile last"

This reverts commit 26f956ddcb49d9c9a310806135ea5a7eb64b217b.
Revert "Revert "Fluid images, mobile last""

This reverts commit 7c65568bf8445a75a7f479f05b1146e29dc136b6.
Sass changes

New linear-gradient mixin, buttons changes, font-smoothing @extend, one
file for all responsive
Sass changes