Styleguide update

Now mentions to always use this.$("...") within Backbone Views.
Refactor Nightwatch

This ticket makes a few changes to the way Nightwatch is set up:
1. the main Nightwatch settings (username, password, login URL, key
nightwatch setup file locations) are moved to the settings.json
file to allow them to be defined a single global place and overridden
if need be.
2. it now dynamically determines the list of tests to run based on
content of settings.json.
3. hardcoded username, password & URL moved from helpers.js and
loginToGUI.js and now loaded from settings.json file

Closes COUCHDB-2481
remove nightwatch.json

it keeps beeing changed
Fix lookaheadTray test

`baseUrl` was undefined
Update Nightwatch README file
verifyinstall addon whitespace and style fixes

Just a housekeeping ticket.
Fix broken testsuite

Remove shared url for db and Fauxton
Move db-url-construction to the settings.json

This enables us additionally to have the couch running on differnt
host to fauxton.
Componentize footer

Take the elements that were all baked into all-docs-list
and inject them into the all-docs-list. This enables us to have
a separate footer component in the layout which can be initialized
without the all-docs-list viewobject.

This enables us to remove the `position: fixed` from the footer
and use `position: absolute`. Without having the element
`position: fixed;` we do not need to calculate it's width via JS
and can apply a css based pane layout.

Part of: COUCHDB-2471
Refactor CSS for pane layout

 - remove JS hack to have fixed elements on a certain size,
   elements now use position absolute/relative and floating

 - header, breadcrumbs and panes do not overlap anymore, which
   lead to alot of bugs like visible but not clickable buttons
   and problems when trying to add new elements to the header

 - header is now aligned with navigantion/burger-height
   (both 64px)

 - componentize footer for all_dbs page

Closes: COUCHDB-2320 COUCHDB-2271 COUCHDB-2471 COUCHDB-2482
with-tabs-sidebar
wip
float-right footer
componentize all-db-footer
fix footer
fix sidebar
Small adjustments for new header size