add more detail to error object

lib/imap.js

@@ -642,6 +642,7 @@ ImapConnection.prototype.connect = function(loginCb) {
         if (line[0] === '+') {
           if (requests[0].cmd !== 'APPEND') {
             err = new Error('Unexpected continuation');
+            err.level = 'protocol';
             err.type = 'continuation';
             err.request = cmdstr;
           } else
@@ -651,6 +652,7 @@ ImapConnection.prototype.connect = function(loginCb) {
           // m[2]: resp-text-code
           // m[3]: message
           err = new Error(m[3]);
+          err.level = 'protocol';
           err.type = 'failure';
           err.code = m[2];
           err.request = cmdstr;
@@ -718,7 +720,9 @@ ImapConnection.prototype.connect = function(loginCb) {
   state.tmrConn = setTimeout(function() {
     state.conn.destroy();
     state.conn = undefined;
-    loginCb(new Error('Connection timed out'));
+    var err = new Error('Connection timed out');
+    err.level = 'timeout';
+    loginCb(err);
   }, this._options.connTimeout);
 };