Merge pull request #1 from vbmithr/master

Mostly doc, plus close(fd) on error.
add OASIS scaffolding for a nonblock_read packet dumper
add a nonblocking test read (not built by default)
bump trunk to 0.5
Merge git://github.com/mirage/ocaml-tuntap

Conflicts:
	_oasis
	myocamlbuild.ml
	setup.ml