restrict inject interval to less that 2^31 millisecs

(596 hrs, 24 days) to stop overflow causing fast loop. (defaults to 0)
to close #1485

nodes/core/core/20-inject.html

@@ -170,6 +170,8 @@ The default payload is a timestamp of the current time in millisecs since Januar
 <p>By default, the node is triggered manually by clicking on its button within the editor. It can also be set to
 inject at regular intervals or according to a schedule.</p>
 <p>It can also be configured to inject once each time the flows are started.</p>
+<p>The maximum <i>Interval</i> that can be specified is about 596 hours / 24 days. However if you are looking at intervals
+greater than one day you should consider using a scheduler node that can cope with power outages and restarts.</p>
 <p><b>Note</b>: The <i>"Interval between times"</i> and <i>"at a specific time"</i> options use the standard cron system.
 This means that 20 minutes will be at the next hour, 20 minutes past and 40 minutes past - not in 20 minutes time.
 If you want every 20 minutes from now - use the <i>"interval"</i> option.</p>
@@ -185,7 +187,7 @@ If you want every 20 minutes from now - use the <i>"interval"</i> option.</p>
             topic: {value:""},
             payload: {value:"", validate: RED.validators.typedInput("payloadType")},
             payloadType: {value:"date"},
-            repeat: {value:"", validate:function(v) { return ((v === "") || (RED.validators.number(v) && (v >= 0))) }},
+            repeat: {value:"", validate:function(v) { return ((v === "") || (RED.validators.number(v) && (v >= 0) && (v <= 2147483))) }},
             crontab: {value:""},
             once: {value:false},
             onceDelay: {value:0.1}

nodes/core/core/20-inject.js

@@ -27,9 +27,14 @@ module.exports = function(RED) {
         this.crontab = n.crontab;
         this.once = n.once;
         this.onceDelay = (n.onceDelay || 0.1) * 1000;
-        var node = this;
         this.interval_id = null;
         this.cronjob = null;
+        var node = this;
+
+        if (node.repeat > 2147483) {
+            node.error(RED._("inject.errors.toolong", this));
+            delete node.repeat;
+        }
 
         node.repeaterSetup = function () {
           if (this.repeat && !isNaN(this.repeat) && this.repeat > 0) {

nodes/core/locales/en-US/messages.json

@@ -61,10 +61,11 @@
         "on": "on",
         "onstart": "Inject once after",
         "onceDelay": "seconds, then",
-        "tip": "<b>Note:</b> \"interval between times\" and \"at a specific time\" will use cron.<br/>See info box for details.",
+        "tip": "<b>Note:</b> \"interval between times\" and \"at a specific time\" will use cron.<br/>\"interval\" should be less than 596 hours.<br/>See info box for details.",
         "success": "Successfully injected: __label__",
         "errors": {
-            "failed": "inject failed, see log for details"
+            "failed": "inject failed, see log for details",
+            "toolong": "Interval too large"
         }
     },
     "catch": {