For a fragment: allow to show a separate note defined in it

 	Turn off preview links locally

support .sass themes

Shift `dependencies` to `devDependencies`.

correct grunt option usage

Remove 'history: true' from index.html

Allow background images without protocols to have query hashes/parameters.

wait for in-slide video/audio to load before playing, reuse same autoplay logic for slide backgrounds

Readme says the default is 'history: false', so it may be surprising
for users - it's easy to miss the contradicting setting in index.html