Replace all `<img>` for icons with Octicon styled `<div>` for non-raster support
Add Octicons resources to GitHub slide deck theme
Consolidate separate CSS resources into one `<link>`, Add Octicons stylesheet
Remove no-longer-used Font-Awesome
Add import of RevealJS sheet directly for easier SASS compression
Remove deprecated no-stretch selector for PNG icons
Flatten GitHub deck theme assets; Remove separate link for RevealJS style
Style cover slide Octicon for greater visual impact
Remove all Octicon raster assets following replacement with Octicons
Merge pull request #169 from github/octicons-no-png

Replace all PNG icons with Octicons