Fix a bunch of bad links.

www/tutorial/wireless.html

@@ -140,9 +140,9 @@ following small example:
 
 <p>
 As mentioned above, there are two different node types with wireless
-interfaces.  The <a href="shownodetype.php3?type=pc3000w"><tt>pc3000w</tt></a> 
+interfaces.  The <a href="/shownodetype.php3?type=pc3000w"><tt>pc3000w</tt></a> 
 nodes are deployed in a wide range around our building.  We have also added a
-single wireless interface to 36 of the <a href="shownodetype.php3?type=pc600">
+single wireless interface to 36 of the <a href="/shownodetype.php3?type=pc600">
 <tt>pc600</tt></a>s.  If you wish to include <b>only <tt>pc3000w</tt></b> nodes
 in your experiment, for each node, set its hardware type:
 
@@ -506,10 +506,10 @@ swap in your experiment!
 <h3<a name="Hardware">Hardware Details</a></h3>
 
 <p>
-The <a href="shownodetype.php3?node_type=pc3000w"><tt>pc3000w</tt></a wifi 
+The <a href="/shownodetype.php3?node_type=pc3000w"><tt>pc3000w</tt></a wifi 
 nodes each contain two 
 <a href="http://netgear.com/products/details/WAG311.php"> Netgear WAG311 
-cards</a>, which use the Atheros 5212 802.11a/b/g chipset.  Each <a href="shownodetype.php3?node_type=pc600"><tt>pc600</tt></a> node
+cards</a>, which use the Atheros 5212 802.11a/b/g chipset.  Each <a href="/shownodetype.php3?node_type=pc600"><tt>pc600</tt></a> node
 contains a single <a href="http://www.dlink.com/products/?sec=0&pid=306">
 D-Link DWL-AG530</a>, which also use the Atheros 5212 chipset.  This chipset is
 quite flexible since most of the 802.11 MAC layer is handled in software.