Shorten @import statement in flow.scss.
Remove line numbers from unit test results.
Refactor example project template to use best practices.

Cherry-pick 55f07316fc25a88e4c1e99152161706019f2a518
Add zengrids.com link to README.
Update gemspec for 2.0.alpha.1
Remove deprecated -experimental-bg-grid() mixin.
Do not import flow module by default.
Add initial zen-grid-background() mixin.
Add $grid-numbers parameter to zen-grid-background()
Rename grid-background module to background.
Add zen-grid-background() mixin. Fixes #25

Merge branch 'grid-background'