fix valgrind mode (-x)

fixes #220
add newline to pid print statement
Merge branch 'master' of https://github.com/shadow/shadow
towards saving debug info

refactor, and iterate the use list to get metadata. now i need
to figure out what to do with the mdnode.

refs #101
quick support for unix sockets

This was a very quick and dirty addition to support unix domain
sockets (AF_UNIX, i.e. AF_LOCAL). Ideally this would be done as
a separate socket subclass.

closes #222
Merge branch 'master' of https://github.com/shadow/shadow