Merge pull request #32 from rackerlabs/bradgignac/line-height

fix(typography): bump line height to 20px
fix(navbar): restore margin beneath navbar

While building out the demo, the navbar margin was set to zero to allow for
multiple navbars (primary, secondary, utility, etc.) to be stacked together.
This broke default Bootstrap behavior and caused margin/padding to be added to
the content. Instead, I've restored the default bottom margin on navbars and
only removed the bottom margin when navbars are sibling elements.
fix(grid): match navbar collapse to grid breakpoints
feat(navbar): skin default navbar

Instead of skinning the default navbar to look like Canon's utility navigation,
simply update the font, background, and border colors to match Canon's visual
design.
feat(navbar): skin inverse navbar

This commit sets font, background, and border colors for the inverted version of
Bootstrap's default navbar. All colors are based on Canon's utility navigation.
feat(navbar): skin utility nav