[New Feature][Issue-47]: Adds new utility class rs-center
[New Feature][Issue-47]: Adds messages screenshot HTML

Messages are being added here to support login screen needs for Reach
[New Feature][Issue-47]: Adds Messages SASS

Messages really belongs in its own branch, but I'm not sure about the best way to split it out and still work on Login...
[New Feature][Issue-47]: Adds info icon to icon sprite
[New Feature][Issue-47]: Adds messages to base Canon SCSS
[New Feature][Issue-47]: Removes overflow hidden from focus panel

After considering the way popovers and login screens may work, it seems best to leave the overflow properties up the the residents of a focus panel rather than the focus panel itself
[New Feature][Issue-47]: Adds Header-Content-Footer structure to the login screen
[New Feature][Issue-47]: Adds Header-Content-Footer structure to login SCSS.

This allows us to move the header and footer outside of the overflow panel, while allowing header and footer to remain centered with the panel