Miscellaneous cleanup

Fix/remove incorrect/redundant comments, remove LIST_OUTPUT cruft, etc.
Project-wide reorganization

Firstly: psdird/psnoded have been rebranded as pstrackd (psnet tracker)
and psrouted (psnet router) respectively.  This really should have gone
in a separate commit, but oh well.

More importantly, the common dependencies of the tracker and router have
been factored out, and the project has been reorganized into three
sub-projects: common, tracker and router.  Common contains code that is
(mostly) used by both the tracker and router.  It builds an archive
(psnet-common.a) for the other projects to build against.

The build system is now recursive in order to better manage this
structure.  Also, some improvements have been stolen from kbuild (the
linux kernel build system), most notably the "cmd" macro and related
stuff for doing less verbose build output.