* Gello being our first pawn
* Use curl instead of wget (more powerful)
* Ensure the intermediates directory exists prior to download
Change-Id: If19c18638a14a8b9ab55470ae6ee5a2deda2e3ec
Run `export WITH_GELLO_SOURCE=true` to build from source. Otherwise,
include artifact from maven repository.
Change-Id: Ie9e0aa23aaaee3bc4ab7048eddd7063fbed531ab