net: doc, doc-inspired cleanup

R=r
DELTA=368  (87 added, 14 deleted, 267 changed)
OCL=25773
CL=25786
diff --git a/src/lib/net/fd.go b/src/lib/net/fd.go
index 0c7770c..501a3f3 100644
--- a/src/lib/net/fd.go
+++ b/src/lib/net/fd.go
@@ -75,7 +75,7 @@
 	cr, cw chan *netFD;	// buffered >= 1
 	pr, pw *os.FD;
 	pending map[int64] *netFD;
-	poll *Pollster;	// low-level OS hooks
+	poll *pollster;	// low-level OS hooks
 }
 func (s *pollServer) Run();
 
@@ -95,7 +95,7 @@
 	if err = setNonblock(s.pw.Fd()); err != nil {
 		goto Error
 	}
-	if s.poll, err = NewPollster(); err != nil {
+	if s.poll, err = newpollster(); err != nil {
 		goto Error
 	}
 	if err = s.poll.AddFD(s.pr.Fd(), 'r', true); err != nil {