Drop experimental prefix from email hint option

Related to #4134
Prefer passing display opts to watch, not request

This patch is backwards compatible.

Console warnings are issued when display options (siteName, siteLogo,
backgroundColor) are passed to .request().

Rationale:

In the future, we hope that browsers will have native support for the BrowserID
protocol. It would be nice if those browsers could display properly themed "sign
into this site" buttons in the native browser UI.

If display options are passed to .request(), they're not known until the user
clicks "sign in" on the site itself. On the other hand, if they're passed to
.watch(), they're known by the browser as soon as the site loads, and can be
used without requiring direct user interaction with the page.

Related to #4134
Stateless (Goldilocks) API ignores ToS / PP

Related to #4134
Warn, but do not ignore, ToS / PP in Goldilocks
Don't allow overriding display options in request
Merge pull request #4142 from mozilla/block-tos-pp-on-goldilocks

Stateless (Goldilocks) API ignores ToS / PP
Merge pull request #4140 from mozilla/email-hint-not-experimental

Drop experimental prefix from email hint option
Merge branch 'display-opts-in-watch' into dev

Conflicts:
	resources/static/include_js/_include.js
Completely overhaul test RP. One page, all APIs.

Still needs CSS and returnTo love, but should be much more functional than
the existing test RP.
Test RP: log options passed to watch/request/get
Add button for calling id.logout from test RP
Merge pull request #4182 from mozilla/overhaul-test-rp

Completely overhaul test RP. One page, all APIs.
Fixing invalid markup

Per https://github.com/mozilla/persona/pull/4182#discussion_r16641241

Now passes http://validator.w3.org/check HTML5 validator.