background update check, now with print-once-only banner
We can assume there is always a latest release installed now.
Don't assign to exports. That breaks circular requires.
make TEST_WAREHOUSE_DIR a non-test thing called METEOR_WAREHOUSE_DIR

(the non-springboarding piece of that is now controlled by
METEOR_TEST_NO_SPRINGBOARD)

This means that run-all-tests.sh can use launch-meteor to bootstrap a warehouse
instead of starting with an empty warehouse directory (which is no longer
allowed).

also, fix npm module usage out of the bootstrap tarball: we were too liberal in
the "never update npm dependencies in the warehouse" rule since the bootstrap
tarball would contain packages with no node_modules (or if we had a failure
between downloading a package and running installNpmDependencies).  instead,
"never update npm dependencies in the warehouse if .npm/node_modules already
exists".
look for an urlBase in release.json (to support binary packages later)
Call "uname plus arch" the "platform".
Normalize to _ (like dev bundle) rather than - (like old releases).
Print "as requested" message in meteor run

(maybe should be others too)
only print override message if using warehouse
update bless-release for new platforms
quote path in bless-release
build arch-specific packages, which contain NPM modules!
packages now per-platform
fix issues
fixes for per-arch packages
use meteor --get-ready instead of --version in places where we're trying to make
sure a checkout is complete
revert addition of urlBase to release.json

it was intended to give us a gateway to arch-specific packages later
but we're doing them now already
Add another newline in overriding message.
fresh files
don't ever call releaseManifestByVersion from the background
A newline