Fix test for 29bce22d0b8c27e2ebcc337586e02159ad4a4f42

Oddly, this test succeeded locally even with the
wrong exception expression. DrDr caught it though.
adjust make-meta-prefix-list and keymap:send-map-function-meta
to only add ~c: when asked to (and then asked them to do it
a bunch)
Rackety: shrink max linewidth to below 102
don't try to load anything to determine if a submodule is present
fix bad edit in a8473ec1aaa2b623b3ce622e4775ceddfbaecf07
add build-farm support to Makefile

The `farm' target run `server', but after the server starts, also
builds clients (via `ssh') as specified in a configuration file.
A client can be a VirtualBox virtual machine, in which case
the client machine can be started and stopped automatically.

Most of the work is in `distro-build/drive-clients' (in the
"distro-build" package), and that's where the configuration-file
format and client-machine requirements are documented.
adjust the props script to work with the new repo layout

dropped the release-notes entries, since those have moved
to places that are hopefully already covered by other props
fix conversion script for props file and re-run

(it had a ~a where it should have had a ~s)

Also, do a get/set this time so the script sorts itself
adjust tut-subst.rkt so that it also supports
untyped languages
Rackety: make contract tests fit in 102 columns
Improve TR timing logging
Browser-to-Racket
Update the browser collection to use Racket lang instead of mzscheme.
fix `local-transformer-expand' with 'top-level context
Several minor doc fixes