pkg: spelling tweaks, I-Z

also, a few miscellaneous fixes to files outside pkg

R=golang-dev, dsymonds, mikioh.mikioh, r
CC=golang-dev
https://golang.org/cl/4517116
diff --git a/src/pkg/syscall/route_bsd.go b/src/pkg/syscall/route_bsd.go
index f0366b0..79a8793 100644
--- a/src/pkg/syscall/route_bsd.go
+++ b/src/pkg/syscall/route_bsd.go
@@ -12,7 +12,7 @@
 
 const darwinAMD64 = OS == "darwin" && ARCH == "amd64"
 
-// Round the length of a raw sockaddr up to align it propery.
+// Round the length of a raw sockaddr up to align it properly.
 func rsaAlignOf(salen int) int {
 	salign := sizeofPtr
 	// NOTE: It seems like 64-bit Darwin kernel still requires 32-bit