Since commit 7aab544, "-f -" before the command broke command
detection, causing spurious "no such option" errors (and breaking
about 70 functional tests which neither I nor travis noticed).
Using "hledgerdev" was a hack to help ensure that tests used a fresh
developer build by default. Now they specify "hledger" again, which fits
better with stack. It's up to the tester to make sure the desired
executable is first in PATH or specified with -w. (Note a couple of
tests currently don't obey -w and will always run "hledger", see addons.test).
This is a workaround for a cmdargs limitation. Having "--debug 2"
or "--width 100" produce no output (because the number is parsed
as a separate argument) is too annoying.
