implement block gutter!
use fluid gutter as default
implement responsive helper mixin with offset parameter
update docs, shortly describe gutter type
mark new feature version 1.1.0
Merge branch 'release/1.1.0'
mark new feature version 1.2.0
Merge branch 'develop' of https://github.com/SimonHarte/responsibly into develop
Merge branch 'release/1.2.0'