Each subdirectory represents a set of related tests.
Each one contains:
* one or more files with names beginning "input-"
The prefix will be stripped and they will be copied
into a new directory before beginning the test.
The script will run from this directory.
* a file "command"
giving the parameters to bernard
* one or more files with names beginning "output-"
Each of these is a test. Its contents will be compared
with a file of the same name in the new directory.
"output-stdout" is a special case; it represents whatever
was printed to stdout.
The comparison is exact, except for the "PO-Revision-Date"
header.
