Sharing: Check if label value is set before to display it

For more details, check the original trac ticket:
http://plugins.trac.wordpress.org/ticket/1974
One line change to fig broken gernericon for Ben
Accessibility: remove unnecessary title attributes

Remove title attributes when they match the anchor text
Sharing: default $title to empty

 so it doesn't break in other functions
Jetpack: Sharing: Consolidating 'Share this' message to one location
Jetpack: Sharing: Adding sanitization function
Jetpack: Sharing: Added default label for sharing on the front end
Verification Tools: Add verification tools module.
After the Deadline: update autosave handling
Props @azaozz

See #38 and original trac ticket:
https://plugins.trac.wordpress.org/ticket/2145
After the Deadline: remove empty files

Props @azaozz
These files are no longer necessary since 92bbbd0099639d6205994d89333ada6a571d967c

See #38 for more details
Twitter Cards: Refactor into a class for Namespace purposes and to be consistent with other Jetpack code.
Twitter Cards: Refactor into a class for Namespace purposes and to be consistent with other Jetpack code.
Merge branch 'twitter-cards-class' of ssh://github.com/Automattic/jetpack into twitter-cards-class
Twitter Cards: Add a field on the sharing screen to configure the twitter:site tag.
Also modifiable from the jetpack_twitter_cards_site_tag filter
Publicize: Add filter to set the twitter:site tag if there's only one shared connection to Twitter.
Use twitter:site tag as default fallback for the 'via' attribute.
Revert "G+ Authorship: Restore the Google+ link at the bottom of the posts."

This reverts commit 67bffe6f4668ff56002ec0608eef264a01ba22f5.

@lezama indicated that he does not know why the changes in 67bffe6f466 were
made, so they are being reverted for consistency with wpcom.
Random redirect: Less fragile detection of the homepage

This merges r88927-wpcom.
Jetpack: Multisite: Fixed redirect while in Network Admin to stay in Network Admin
SSO: Switch from adding to general options

Instead use a Jetpack options page.