Just so everyone knows, most of the jobs in build.squeak.org are red.
I'm revamping the build pipeline so that, where appropriate, jobs can
build on the binaries built by earlier jobs.

So SqueakTrunk produces, from a base image, an updated image in the
form of TrunkImage.zip
ReleaseSqueakTrunk unzips this, runs the release process, (runs tests
on the artifact) and produces a new artifact, Squeak4.5.zip
ExternalPackages jobs unzip TrunkImage.zip, loads a package, and runs tests.

And so on.

Probably, we need to break the ExternalPackages jobs into one package
+ one VM jobs (so ExternalPackages-Fuel-Interpreter,
ExternalPackages-Fuel-Cog). We have the pieces for doing all this
already; it's mainly just setting up new build configurations.

(As an aside, I tweaked Jenkins' startup parameters to try optimise
its memory use. Perversely, this made its memory use _worse_, so I've
reverted the change. build.squeak.org should once more be stable, or
at least as stable as before.)

frank