ce: Use a better transparent pixel image

See also http://stackoverflow.com/a/13139830/319266:

> Some are unstable and cause CSS glitches. [If] you have an
> <img> and you use the tiniest transparent GIF possible, it
> works fine[. if] you then want your transparent GIF to have a
> background-image, then this is impossible. For some reason,
> some GIFs such as the following prevent CSS backgrounds (in
> some browsers).
>
> == Shortest (but unstable) ==
> data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw==
>
> == Stable (but slightly longer) *use this one* ==
>
> data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7
>
> Also: don't ommit image/gif. This will break in several browsers.

For the record, this is not limited to rare browsers.
It also affects latest Chrome in some cases as confirmed by
Christian (it'd be white instead of transparent in some cases
when uses as a css background-image without border).

Change-Id: If9ff8a0820c217b6c23e3335944907939a37bef7
Merge "ce: Use a better transparent pixel image"