v2.1.0

Summary

• Added new .centered utility class for grid columns and more
• Removed a bunch of undocumented github/github-specific CSS
• Updated to latest Normalize
• Improved button states
• Misc fixes to docs and build tools

CSS

• #53, #104: Remove overrides to .btn's box-shadow when in button groups to avoid a broken :focus state
• #55, #87: Improve behavior and styling for more button states
• #56: Add utility layout class, .centered, to center content and grid columns
• #64, #86: Remove the undocumented github/github-specific CSS
• #83: Update Normalize.css to v3.0.3
• #90: Document and fix the use of <form>s in button groups with .button_to.

Docs

• #29: Add note on SCSS' overloaded rgba() function
• #81: Add version to the docs footer
• #82: Update @import guidelines in the readme
• #89: Reiterate our CSS guidelines are for SCSS
• #98: Add guideline about soft-tabs for HTML
• #96, #97, #103: Update some typos, fix Markdown, and remove expletives from the docs
• #101: Removed CLA text from the repository in favor of the CI service

Tooling

• #91: Properly configure Hound CI
• #99: Update our SCSS lint file to use the latest property order syntax and remove vendor prefixes