On the run in which steamcmd replaces itself, the app_update that follows fails
with 'Missing configuration', and the same command succeeds once it runs again.
A login-only run first takes that self-update out of the install and update.
Replaces the misc/build.func bootstrap with the two-root core loader.
No other change: the engine contract (var_*, update_script, start,
build_container, description) is identical on both engines.
versitygw.sh additionally gains a trailing newline; it lacked one.
With this batch every ct/ script is on the core engine.
CanbiZ (MickLesk)