Add Nex-Tech Wireless as a provider

lib/carriers.js

@@ -27,6 +27,9 @@ module.exports = {
   cricket: [
     '%s@sms.mycricket.com',
   ],
+  nex-tech: [
+    '%s@sms.ntwls.net',
+  ],
   tmobile: [
     '%s@tmomail.net',
   ],

lib/providers.js

@@ -11,6 +11,7 @@ module.exports = {
     '%s@pcs.rogers.com',
     '%s@qwestmp.com',
     '%s@sms.mycricket.com',
+    '%s@sms.ntwls.net',
     '%s@tmomail.net',
     '%s@txt.att.net',
     '%s@txt.windmobile.ca',