Ensure image URLs returned end with a graphic extension
Ensure image URLs returned end with a graphic extension

Lifted liberally from hubot's Google image search[1]. Blindly appends
a graphic extension to a URL if it does not end in one so that chat
clients attempt to treat the URL as a graphic.

Does not solve the problem of Google returning a URL with junk at the
end that causes the real site to go WTF?

[1] https://github.com/hubot-scripts/hubot-google-images/blob/v0.1.4/src/google-images.coffee#L46-L51
markolson/linkbot