Fix file descriptor leak

[cgay]

cgay@lovelace:~/dylan-wiki$ ps -ef | grep org
cgay 14463 1 0 13:55 pts/3 00:00:04 opendylan-dot-org --config /home/cgay/dylan-wiki/config.xml
cgay 28104 31095 0 15:59 pts/1 00:00:00 grep org

cgay@lovelace:~/dylan-wiki$ lsof | grep cgay | grep pipe | grep opendylan | wc -l
298

The wiki has been up for just over two hours, with only my using it lightly, and has 300 pipes open. I have to assume this is related to running rst2html or some other call to run-application.

Write a test to verify that fds get closed properly for those calls.

[hannesm]

should be fixed by my recent commit (was a problem in run-application which leaked the read-fd). please verify if it's good now