add _sassyExist.scss
add column and gutter classes to API.md
update grid API
add core functionality for SassyExists plugin
add SassyExist type validation
add Grid config map
add Grid README.md with todos and ideas
update SassyExists _demo.scss
add susy global configs
update grid config map
add responsive gutters comment
fix is_empty function
add file name notes
rename _webFonts.scss => _webFontsInclude.scss
update sassdoc
Merge branch 'feature/sassyvalidation' into develop