We might change some notmuch command line tools that used to be
booleans into keyword arguments.
In that case, there are some legacy tools that will expect to be able
to do "notmuch foo --bar" instead of "notmuch foo --bar=baz".
This patch makes it possible to support that older API, while
providing a warning and an encouragement to upgrade.
The files (test) scripts source (with builtin command `.`) provides
information which the scripts depend, and without the `source` to
succeed allowing script to continue may lead to dangerous situations
(e.g. rm -rf "${undefined_variable}"/*).
At the end of all source (.) lines construct ' || exit 1' was added;
In our case the script script will exit if it cannot find (or read) the
file to be sourced. Additionally script would also exits if the last
command of the sourced file exited nonzero.
All test scripts to be executed are now named as T\d\d\d-name.sh,
numers in increments of 10.
This eases adding new tests and developers to see which are test scripts
that are executed by test suite and in which order.
