Fix multiple email handling in the Inbox.

Put an email regex into WebGUI::Utility, and use it in Form/Email and Account/Inbox.

lib/WebGUI/i18n/English/Account_Inbox.pm

@@ -470,8 +470,13 @@ our $I18N = {
         lastUpdated => 1181409056,
     },
 
+    'too many emails' => {
+        message => q|The invitation cannot be sent because you did not enter an email address.|,
+        lastUpdated => 1181409056,
+    },
+
     'missing message' => {
-        message     => q|Your invitiation must have a message.|,
+        message     => q|Your invitation must have a message.|,
         lastUpdated => 1181409432,
     },