Add default values for outstreams in dulwich.porcelain.
Remove --backend option from dulwich.server.main.
Add some tests for FileSystemBackend and DictBackend.
Add porcelain 'daemon'.

Remove dul-daemon script, and replace with 'dulwich daemon'.
Release 0.9.7.
Start on 0.9.8.
Merge branch 'master' of git://github.com/jelmer/dulwich