fix to Issue4: lettuce failure due to corrupted logs

This branch implements the proposed solution described in
https://github.com/bundy-dns/bundy/issues/4

The diff is big, but most of them are trivial editorial changes:

- most changes under configurations/ are to embed placeholder to replace at run time
- most changes for .feature files are straightforward substitution from "stderr" to "log"

Basically, the only non-trivial things are changes to the python files under features/terrain/.

I ran the lettuce tests with these changes, and it worked quite well.  There are some intermittent failures in xfrin_notify_handling, but that seems to be a different problem (I vaguely recall it happened in BIND 10, too, and that's a timing problem).