drop -iprange from proxy docs, since ipam is enabled by default now

site/proxy.md

@@ -87,13 +87,9 @@ can be started in foreground mode, and can be automatically removed
 ## <a name="ipam"></a>Automatic IP address assignment
 
 If [automatic IP address assignment](ipam.html) is enabled in weave,
-e.g. by launching it with
-
-    host1$ weave launch -iprange 10.2.3.0/24
-
-then containers started via the proxy can be automatically assigned an
-IP address by providing a blank `WEAVE_CIDR` environment variable, as
-in
+which it is by default, then containers started via the proxy can be
+automatically assigned an IP address by providing a blank `WEAVE_CIDR`
+environment variable, as in
 
     host1$ docker run -e WEAVE_CIDR= -ti ubuntu
 
@@ -138,12 +134,12 @@ they can reach each other by name.
 First, let us start weave, weaveDNS and the proxy, and set DOCKER_HOST
 to point at the latter:
 
-    host1$ weave launch -iprange 10.2.3.0/24
+    host1$ weave launch
     host1$ weave launch-dns 10.2.4.1/24
     host1$ weave launch-proxy --with-ipam
     host1$ eval "$(weave proxy-env)"
 
-    host2$ weave launch -iprange 10.2.3.0/24 host1
+    host2$ weave launch host1
     host2$ weave launch-dns 10.2.4.2/24
     host2$ weave launch-proxy --with-ipam
     host2$ eval "$(weave proxy-env)"