contact form: RTL support for the form editor, fixes #6840

See https://github.com/Automattic/jetpack/pull/1261

Merges r108236-wpcom.
Contact form RTL: use tahoma by default

See https://[private link]?topic_id=547539

Merges r108437-wpcom.
Merge commit '6246b18'
REST API: allow the returned HTTP code to be changed from 200 for successful actions.

This change is implemented because upcoming endpoints for site import/exports need to return a HTTP 202 response.

Props to @mdawaffe for the patch. :)
See https://[private link]

Merges r107424-wpcom.
REST API: move the CORS/preflight action to fire before authentication is processed.

Firefox does not pass authorization headers when executing OPTIONS/preflight requests whereas other browsers do. Apparently (http://stackoverflow.com/a/15734032) this is actually in par with the spec, though there's an effort to change the spec. Because the authorization headers are not passed in, some requests would fail at the authentication process and thus not return the preflight headers. I believe that the problem was amplified in production where prefork kicks in.

This simply moves the actions associated with the preflight headers to fire before authentication is verified. I've also added some tests for preflight requests since we didn't have any. However these tests don't cover browser inconsitencies like this one.

see https://[private link]

Merges r107759-wpcom.
revert [107759] as it didn't solve the problem with CORS and firefox

Merges r107760-wpcom.
REST API: adjustments to CORS/preflight

* Move the action to fire before authentication is processed. Authentication shouldn't be necessery for the preflight requests. Originally deployed in [107759] but later reverted.
* Explicitly output with a 200 status for preflight requests

This is an attempt to fix a production/firefox specific issue. However even if it doesn't fix the issue, these improvements still make sense as they do not cause any regressions and make the output a bit cleaner for these requests.
see https://[private link]

Merges r108139-wpcom.
Merge commit '1a1c163'
Store: REST API: Adding a cart_item definition to the API documentation and using it for the shopping cart endpoint.

Part of https://[private link]

Merges r107784-wpcom.
REST API: /me/posts endpoint. Return the Jetpack author.

We were returning the wpcom user data instead of returning the Jetpack author data stored on post_meta for jetpack sites.

See:
https://github.com/Automattic/calypso-pre-oss/issues/1465
https://[private link]#comment-618

Merges r108070-wpcom.
REST API: /me/posts Endpoint: Improve readability of r108070

See: https://a8c.slack.com/archives/api/p1415109581000761

Merges r108079-wpcom.
REST API: v1.1 publicize connection metadata

* Adds methods for generating meta links for publicize connections, keyring tokens and external services
* Adds meta links for publicize connection endpoints
* Consolidates how publicize-connections are formatted for output in those endpoints
* Adds tests for metadata and consolidates test requests

see https://github.com/Automattic/calypso-pre-oss/issues/1330

Merges r108747-wpcom.
Merge commit '95be6b4'
REST API: Extend site settings endpoint with additional sharing options

Specifically, `disabled_likes`, `disabled_reblogs`, `jetpack_comment_likes_enabled`, and sharing `open_links`

See: https://github.com/Automattic/calypso-pre-oss/issues/1334

Merges r108275-wpcom.
REST API: Ensure publicize delete endpoint returns int ID of connection deleted

Per response format, cast ID of deleted connection to int

Merges r108611-wpcom.
JP Likes / Sync: Pulling in changes to keep JP and WPCOM files in sync.

Changes are for GH issue #697 and deals with syncing posts when only the likes
module is enabled.

See:
https://github.com/Automattic/jetpack/issues/697

Merges r104285-wpcom.
Likes: in the Posts list view in wp-admin, hide the Likes column on small screens.

Merges r106968-wpcom.
Likes: Bump cachebuster to pick up new JS (with added adminbar stat).

Merges r107653-wpcom.
Include post-MP6 styles for Likes in the post listing page.

Merge commit 'a234b19'

Conflicts:
	modules/likes.php
Widget Top Posts: Don't fiddle with the number of posts selected by the user, even if it makes odd image grids.
See: https://[private link]

Merges r108117-wpcom.