(#1859) - Performance tests for map/reduce

Adds performance tests for mapreduce, testing:
* temp views
* persistent views
* persistent views w/ stale=ok
(#1910) - more fully cancel changes
(#1460) - always cancel changes when db is destroyed
(#1907) - Make adapters responsible for cleaning their own data
(#1923) - Enable safari in travis
(#1925) - Fail early when running browser tests on saucelabs
(#1901) - Added github ribbon
(#1574) - Website icons
(#1945) - remove errent crypto use
(#1919) - specify script/adapter for perf tests

This commit allows you to pass the script src or
adapter (e.g. 'websql') as options to the URL of
the performance tests.
(#1926) - More efficient changes() for idb/websql

This moves more of the limit/doc_ids filtering logic
up-front, so that we don't have to read the entire
changes stream into memory and then filter at the end.

This also fixes an error with 'rev' in websql when
the docid contains the '\u0000' character.
(#44) - Add localstorage-down to Travis tests
(#1942) - cleanup uuids code
(#1711) - Front page blog post
(#1938) - updates to package.json
(#1934) - publish pagination blog post
(#1750) - Clarify fully supported browsers vs experimental
(#1916) - clean up db.replicate.foo and break sync out into its own module
(#1921) - returnDocs in the browser
(#1350) - use new style api for changes in examples