Fixed #113: SUG: Support safebooru.org, etc.
Fixed #110: Pinterest

Fixed #108: TZP stops working on Nightly ff21.0 (ff20 too?)

Explicitly clears onerror.  Tested successfully in ff20 and 21.0a2, 22.0a1.

Also fixed (?) an intermittent problem with 'g' search for current image on Google Images.