Update plugin banner image, screenshot, examples

[jaredatch]

With the 1.1.0 release we no longer track LinkedIn counts (they removed their API) and added support for Yummly share counts. We should update the plugin banner image and screenshot to reflect this.

[jaredatch]

We still support LinkedIn button, just not tracking. However G+ button has been pulled entirely, so that should be removed from banner image, screenshots, and style examples ideally.

[jaredatch]

Marking this for potential in 1.4, or whenever the FB rebrand goes live.

[jaredatch]

When we address this, I think we should also add screenshots Google Analytics (and we can note in the caption automatic share tracking) and maybe the settings.

And at the same time, we should make a section in the readme about Google Analytics tracking because that's a pretty awesome feature that is totally worth pointing out :)

[billerickson]

Per the new Trademark Enforcement post, we need to remove all trademark logos from the header image. So the share buttons should just be colored buttons, not including the actual logo.