Adding eLife Lens as an example app.
Adding a do-not-post-if section to CONTRIBUTING
Giving CONTRIBUTING a more accurate title.
remove null options guard

no need to check for null options here as the first line of the
function already assumes an options object.
Merge pull request #2702 from hartzler/remove-unreachable-code

remove null options guard
Fixes #2684 -- tweak toJSON docs.
Merge branch 'master' of https://github.com/jashkenas/backbone
use shorter form for comparator
fixed two stand-out typos :)
Restore "elan".
Merge pull request #2706 from akre54/comparator-docs

Update comparator example in the docs