use status -2 for 404s

human_status (response.js) defines code -2 as 'user error'. 404 is definitely a user error, so using that makes sense.
eventually we should change the whole status code thing with #120

lib/routes/avatars.js

@@ -52,8 +52,9 @@ module.exports = function(req, callback) {
   // check for extra paths
   if (req.url.path_list.length > 2) {
     callback({
-      status: -3,
-      body: "Invalid URL Path"
+      status: -2,
+      body: "Invalid Path",
+      code: 404
     });
     return;
   }

lib/routes/capes.js

@@ -11,8 +11,9 @@ module.exports = function(req, callback) {
   // check for extra paths
   if (req.url.path_list.length > 2) {
     callback({
-      status: -3,
-      body: "Invalid URL Path"
+      status: -2,
+      body: "Invalid Path",
+      code: 404
     });
     return;
   }

lib/routes/renders.js

@@ -62,8 +62,9 @@ module.exports = function(req, callback) {
   // check for extra paths
   if (req.url.path_list.length > 3) {
     callback({
-      status: -3,
-      body: "Invalid URL Path"
+      status: -2,
+      body: "Invalid Path",
+      code: 404
     });
     return;
   }

lib/routes/skins.js

@@ -59,8 +59,9 @@ module.exports = function(req, callback) {
   // check for extra paths
   if (req.url.path_list.length > 2) {
     callback({
-      status: -3,
-      body: "Invalid URL Path"
+      status: -2,
+      body: "Invalid Path",
+      code: 404
     });
     return;
   }