Update portfolios.php

Added order and orderby options to the portfolio shortcode
Update portfolios.php

Sanitized orderby option
Update portfolios.php

Mistake in constructing the argument to orderby - argument is now a space separated string rather than an array.
Allow uppercase arguments to order option

Converts the order option to upper case before checking the value. Allows users to use upper, lower, or a combination in the shortcode and ensures that the argument is uppercased before passed to WP_Query.
Site Icon: Remove trailing whitespace
Social Meta Tags: add Site Logo and Site Icon fallback

When no image is found in a post, use fallbacks to build an Open Graph Image tag and a Twitter Card
Site Icon: the icon should be 512px minimum
Twitter Cards: fallback if there is no existing image card
Nova Menu CPT: fix notice when we have no taxonomies

Notice: Undefined variable: term_id in ...wp-content\plugins\jetpack\modules\custom-post-types\nova.php on line 965
Limited orderby option

Update ensures that the `orderby` option is now limited to `author`, `date`, `title`, `rand` and combinations of these seperated by a comma. Invalid keys are skipped, and a space seperated string is created for passing through to `WP_Query`. The array item is unset if no appropriate values are entered so it will pick up the default in `WP_Query`.
Add XMLRPC endpoint to refresh publicize conns.

We are introducting v1.1 of publicize connection endpoints in the WP.com/Jetpack REST API.

Because all information about keyring tokens and publicize connections is stored on WordPress.com and not on the remote Jetpack side, we are not going to duplicate these endpoints in Jetpack proper. Instead, we're adding Jetpack support by keeping the code for the endpoints on WordPress.com only.

These new endpoints allow both the creation and deletion of publicize connections on the remote Jetpack site. In order for the sharing options page to be up to date on the Jetpack site, we need to update the `publicize_connections` Jetpack option whenever a connection is added or removed on the WP.com side.

To do so requires remotely forcing the refresh of the `publicize_connections` option. Previously, this option was only refreshed when a connection was completed from the Jetpack site via the sharing page UI. Now we also allow refreshing this option via a remote XMLRPC call, which will be triggered from the WP.com JSON API endpoint.
Receive publicize connections instead of fetching them

Miguel suggested:

> it would be better if we send the publicize connections directly on the new xmlrpc call instead of asking the remote site to fetch them. It will make the endpoint faster.

So the endpoint now receives the publicize connections and updates the option rather then performing another fetch operation. The WordPress.com side of this has been updated as well.
Nova Menu CPT: make sure the function always returns something

As per https://github.com/Automattic/jetpack/pull/1303#discussion_r21246932
Top Posts Widget: refactor to allow conditional loading of the css

Move the CSS file to its own folder, to stay consistent with other
widgets and keep things organized

Use wp_enqueue_scripts instead of wp_print_styles so the css is
only loaded when necessary
Top Posts Widget: update path for CSS concatenation
Top Posts Widget: use dashes instead of underscores in slug
Site Icon: add missing parameter to jetpack_site_icon_url

See https://github.com/Automattic/jetpack/pull/1280#discussion_r21246458
Save Site Icon URL into Jetpack Options

This allows the site icon to sync with WordPress.com.
Set up syncing of site icon URL
Change URL to 512px version