lib/str.sh gains firstword, lastword, or, patsubst, filter, filter_out,
addprefix, addsuffix and jwt: what the catalogue .mk files are written in.
The make JWT macro split on the commas of its payload; this one does not.
lib/context.sh registers COMPOSE_PROJECT_NAME, APP, DOCKER_NETWORK_* and the
rest as lazy defaults, so a converted .mk keeps reading them as it did.
Hooks also load a directory-level _stack.env and _stack.sh, for the .mk files
of the catalogue that hold settings for several stacks at once.
Yann Autissier
6192d73cbe