up version to 2.2.0-alpha
(#113) - Initial infrastructure for performance testing
(#1834) - More performance tests

Also updated CONTRIBUTING.md to explain how
to access performance tests.
(#1821) - Fix hotlink
(#1765) - Make npm run build-site rebuild css on less changes
(#113) - Ensure perf tests get build on first run (and tweak docs)
(#1752) - Scrollspy on side nav on api page
Minimum changes necessary for pouchtest.com