Fix confusing unseen mailbox count behavior

README.md

@@ -201,7 +201,7 @@ node-imap exposes one object: **ImapConnection**.
     * **messages** - <_object_> Contains various message counts for this mailbox:
         * **total** - <_integer_> - Total number of messages in this mailbox.
         * **new** - <_integer_> - Number of messages in this mailbox having the Recent flag (this IMAP session is the first to see these messages).
-        * **unseen** - <_integer_> - Number of messages in this mailbox not having the Seen flag (marked as not having been read).
+        * **unseen** - <_integer_> - **(Only available with status() calls)** Number of messages in this mailbox not having the Seen flag (marked as not having been read).
 * _ImapMessage_ is an object representing an email message. It consists of:
     * Properties:
         * **seqno** - <_integer_> - This message's sequence number. This number changes when messages with smaller sequence numbers are deleted for example (see the ImapConnection's 'deleted' event). This value is **always** available immediately.

lib/imap.js

@@ -72,7 +72,7 @@ function ImapConnection (options) {
       keywords: [],
       permFlags: [],
       name: null,
-      messages: { total: 0, new: 0, unseen: 0 }
+      messages: { total: 0, new: 0 }
     },
     ext: {
       // Capability-specific state info
@@ -415,7 +415,7 @@ ImapConnection.prototype.connect = function(loginCb) {
               messages: {
                 total: 0,
                 new: 0,
-                unseen: 0
+                unseen: undefined
               }
             };
             if (m.attributes) {
@@ -469,9 +469,7 @@ ImapConnection.prototype.connect = function(loginCb) {
             } else if (/^ALERT$/i.test(code))
               self.emit('alert', m[3]);
             else if (state.status === STATES.BOXSELECTING) {
-              if (m = /^UNSEEN (\d+)/i.exec(code))
-                state.box.messages.unseen = parseInt(m[1], 10);
-              else if (m = /^UIDVALIDITY (\d+)/i.exec(code))
+              if (m = /^UIDVALIDITY (\d+)/i.exec(code))
                 state.box.uidvalidity = parseInt(m[1], 10);
               else if (m = /^UIDNEXT (\d+)/i.exec(code))
                 state.box.uidnext = parseInt(m[1], 10);
@@ -1254,7 +1252,6 @@ ImapConnection.prototype._resetBox = function() {
   this._state.box.name = null;
   this._state.box.messages.total = 0;
   this._state.box.messages.new = 0;
-  this._state.box.messages.unseen = 0;
 };
 
 ImapConnection.prototype._noop = function() {