Merge branch 'master' into gh-pages

Conflicts:
	markdown/cc.md
Update submodule URLs
Revert reveal.js submodule to upstream
Merge branch 'master' into gh-pages

Conflicts:
	.gitmodules
Switch to reveal.js dev branch (with audio playback support)
Add narration support
Add audio narration
Merge branch 'narrated' into gh-pages

Conflicts:
	.gitmodules
Drop audio symlinks
Merge branch 'narrated' into gh-pages
Bump autoslide to 5 seconds
Merge branch 'narrated' into gh-pages
Re-enable progress bar and controls
Drop audio recording support

Use audio playback only.
Update audio narration
Merge branch 'narrated' into gh-pages
Fix audio edit
Merge branch 'narrated' into gh-pages
Merge branch 'gh-pages' into hastexo-gh-pages

Conflicts:
	.gitmodules
	markdown/cc.md