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
Add Option tray now uses generic component

To test this, just click on the Add Option header link on the
Config page.

Closes COUCHDB-2453
Style fix for Add Database tray

Very small thing. The rounded corners should only appear on the left of the
input box in the Add Database tray. This increases the specificity of the
rule so it properly applies.
init
initial view
dev build
wip
add icon
s/hostname/host/