WIP: User Interrupt Queue

* All queueing of messages/etc.
* Queueing across nodes
* Start on interruption points for displaying queued items
* Start on a multi-node messaging system using such a queue

core/user_interrupt_queue.js

@@ -0,0 +1,58 @@
+/* jslint node: true */
+'use strict';
+
+//  ENiGMA½
+const Art                   = require('./art.js');
+const {
+    getActiveConnections
+}                           = require('./client_connections.js');
+const ANSI                  = require('./ansi_term.js');
+
+//  deps
+const _     = require('lodash');
+
+module.exports = class UserInterruptQueue
+{
+    constructor(client) {
+        this.client         = client;
+        this.queue          = [];
+    }
+
+    static queueGlobal(interruptItem, connections) {
+        connections.forEach(conn => {
+            conn.interruptQueue.queueItem(interruptItem);
+        });
+    }
+
+    //  common shortcut: queue global, all active clients minus |client|
+    static queueGlobalOtherActive(interruptItem, client) {
+        const otherConnections = getActiveConnections(true).filter(ac => ac.node !== client.node);
+        return UserInterruptQueue.queueGlobal(interruptItem, otherConnections );
+    }
+
+    queueItem(interruptItem) {
+        interruptItem.pause = _.get(interruptItem, 'pause', true);
+        this.queue.push(interruptItem);
+    }
+
+    hasItems() {
+        return this.queue.length > 0;
+    }
+
+    display(cb) {
+        const interruptItem = this.queue.pop();
+        if(!interruptItem) {
+            return cb(null);
+        }
+
+        if(interruptItem.cls) {
+            this.client.term.rawWrite(ANSI.clearScreen());
+        } else {
+            this.client.term.rawWrite('\r\n\r\n');
+        }
+
+        Art.display(this.client, interruptItem.contents, err => {
+            return cb(err, interruptItem);
+        });
+    }
+};