support R16B01

Due to non-OTP-ness, couch need to start its own OTP apps. R16B01
requires asn1 as a dependency for public_key.
Closes COUCHDB-1833.
Add a configurable whitelist of public user props

By default no user properties are public and attempts to view a users
document other than your own will return a 404. If the public_fields
setting of the users_db config section is set to a list of field
names, however, you will see that subset of fields for any user.

Also, if `public_fields` is set and non-empty,
`_users/_all_docs?include_docs=true` will return documents with stripped
field.

Contributed with code parts from @indutny
move watch files to settings.json
Fauxton: Set active nav tab

When a nav tab is clicked on that tab is now highlighted.
This fixes COUCHDB-1842
[tests] tidy up etap stream test output

Closes COUCHDB-1082.
Use Array#forEach instead of for .. in

Also improved the wording in a few places.
Fauxton: Add dependancies to watch path instead of custom watch path
Fauxton: Change select header to data attribute
Fauxton: watch assets path
Fauxton: remove route events from main.js
Remove branch instructions from Fauxton readme
Expanded description of the validate_doc_update function
Fix database info's instance_start_time field description