(#1732) Batch replicate one generation docs

Update of @jo fix for #993. Use allDocs to speed up replicate of one gen. docs.
(#1735) - Bring back the browser migration tests

It looks like we accidentally regressed in
13839c64c0f0915a4b9490d8d638bc59ccb35ef4
and browser.migration.js stopped working.
(TypeError: PouchDB is not defined.)
(#1725) - proper prefixes for view dbs
(#1716, #1722) Sidebar is fixed, has API links on api.html and nav links otherwise.

Layout for 2 column pages is 2ColLeft.html.
Sidebars are in _includes/, API is api.html and nav is nav.html.
Sidebar is fixed if window has width >= 770px and height >= 475px.
(#1704) decreased width of blog