ShareDaddy: No double @'s.

This will prevent a tweet from looking like `via @@Viper007Bond` if the
via parameter is prefixed with an @.
Merge pull request #396 from Automattic/ui-tweaks-dave

Dashboard banner CSS
Add some padding to the drop zone to make it match the new ui.
Default to displaying sharing counts.

This will enable counts output on the icon-only variant as well.
Merge pull request #395 from Automattic/twitter-via-double-at

ShareDaddy: No double @'s.
Merge pull request #397 from Automattic/ShareDaddy-New-UI-Fixes

Share daddy new ui fixes
Tidy up height of checkbox.

Fixes this issue: https://cloudup.com/cf57xSujZo3
Merge pull request #410 from Automattic/ShareDaddy-New-UI-Fixes

Tidy up height of checkbox.
Better visual indication of active modules

- Added 4px blue border-left to active modules
- Fixed line-height issues with “activate link
- Lightened opacity on module icons just a tad