Don't allow @ in package names

Author: isaacs

lib/utils/read-json.js

@@ -72,10 +72,10 @@ function processObject (opts, cb) { return function (er, json) {
     if (cb) return cb(e)
     throw e
   }
-  if (json.name.charAt(0) === "." || json.name.match(/\//)) {
+  if (json.name.charAt(0) === "." || json.name.match(/[\/@]/)) {
     var msg = "Invalid name: "
             + JSON.stringify(json.name)
-            + " may not start with '.' or contain '/'"
+            + " may not start with '.' or contain '/' or '@'"
       , e = new Error(msg)
     if (cb) return cb(e)
     throw e