Whitespace and style fixes

Updated styles for the Active Tasks add-on.
- ‘ not “
- underscore comments
- whitespace fixes
- removed a couple of unused vars
Remove API Url link from header on Access Denied page

Closes COUCHDB-2436
Unify one_pane and one_pane_db again

We recently introduced a new template `one_pane_db` which had
the rightHeader for the list of DBs. In retrospective it turns
out that also other views need the rightHeader markup to
populate it with elements.

Views that don't need the rightHeader element should not get
influenced so this removes some complexity and avoids that the
templates diverge more in the future.
Replicate icon on Databases page now redirects properly

Closes COUCHDB-2437
Fix path for ZeroClipboard

If deployed as an CouchApp, the path for ZeroClipboard did not
match

Steps to reproduce:
 - run `grunt couchapp_deploy` with a Couch in Admin-Party
 - open http://localhost:5984/fauxton/_design/fauxton/index.html

Closes COUCHDB-2323
Whitespace & style fixes
Fix back-button after you saved a new document

When you were creating a new document and then clicking save
the back button would bring you to the editor for new documents.
To get back to the Documentslist you were coming from, you had
to hit the "back"-button twice.

Additionally renamed lastPage to lastPages as it contains
multiple pages.
Write up expectations we have for contributions

 - mention styleguide
 - mention commit message format
 - small bugfixes do not need a Jira ticket
Replaced couple of hardcoded vars with constants
Moved Add Config Option modal to tray

This also fixes a few things.
- validation is cleaned up a bit
- the typeahead option now properly works again for sections.

Closes COUCHDB-2443
New lookahead-tray component

You can see the component by going to a database, then clicking on
the database name. That will open up a tray where you can type to
get a list of other matching databases. Clicking <enter> or
selecting the item from the list will take you to that particular
DB page.

Closes COUCHDB-2420
Create generic Tray component

This moves a lot of the logic from the individual trays (Add Database,
Query Options, API Url) and into a generic Tray component.

Closes COUCHDB-2401
Fix for Query Options search

Closes COUCHDB-2451