Shell tests don't work when run from ProjectFortress

[jmaessen]

Look at trunk:ProjectFortress/tests/concurrentPrinting.sh and note that it uses a bunch of relative paths that only make sense when tests are run from the root of the trunk. My feeling is that we should be setting the FORTRESS_HOME environment variable in the wrapper and then using that inside the script. An alternative would be to cd to a fixed location (preferably the tests directory itself) before running a shell test. In any case, we ought to do something so that we don't accidentally work from the wrong place.

I've added a bit of mechanism to this script to try to do the right thing, but I don't think my use of "dirname" is portable.