Display warning banner when plugins are modified

Fixes #1455

@aelocson have I got the docs right for the new filter?

core/language/en-GB/Misc.multids

@@ -14,6 +14,7 @@ Encryption/ConfirmClearPassword: Do you wish to clear the password? This will re
 Encryption/PromptSetPassword: Set a new password for this TiddlyWiki
 InvalidFieldName: Illegal characters in field name "<$text text=<<fieldName>>/>". Fields can only contain lowercase letters, digits and the characters underscore (`_`), hyphen (`-`) and period (`.`)
 MissingTiddler/Hint: Missing tiddler "<$text text=<<currentTiddler>>/>" - click {{$:/core/images/edit-button}} to create
+PluginReloadWarning: Please save {{$:/core/ui/Buttons/save-wiki}} and reload {{$:/core/ui/Buttons/refresh}} to allow changes to plugins to take effect
 RecentChanges/DateFormat: DDth MMM YYYY
 SystemTiddler/Tooltip: This is a system tiddler
 TagManager/Colour/Heading: Colour

core/modules/filters/haschanged.js

@@ -0,0 +1,36 @@
+/*\
+title: $:/core/modules/filters/haschanged.js
+type: application/javascript
+module-type: filteroperator
+
+Filter operator returns tiddlers from the list that have a non-zero changecount.
+
+\*/
+(function(){
+
+/*jslint node: true, browser: true */
+/*global $tw: false */
+"use strict";
+
+/*
+Export our filter function
+*/
+exports.haschanged = function(source,operator,options) {
+	var results = [];
+	if(operator.prefix === "!") {
+		source(function(tiddler,title) {
+			if(options.wiki.getChangeCount(title) === 0) {
+				results.push(title);
+			}
+		});
+	} else {
+		source(function(tiddler,title) {
+			if(options.wiki.getChangeCount(title) > 0) {
+				results.push(title);
+			}
+		});
+	}
+	return results;
+};
+
+})();

core/ui/PageTemplate/pluginreloadwarning.tid

@@ -0,0 +1,22 @@
+title: $:/core/ui/PageTemplate/pluginreloadwarning
+tags: $:/tags/PageTemplate
+
+\define lingo-base() $:/language/
+
+<$list filter="[has[plugin-type]haschanged[]limit[1]]">
+
+<$reveal type="nomatch" state="$:/temp/HidePluginWarning" text="yes">
+
+<div class="tc-plugin-reload-warning">
+
+<$set name="tv-config-toolbar-class" value="">
+
+<<lingo PluginReloadWarning>> <$button set="$:/temp/HidePluginWarning" setTo="yes" class="tc-btn-invisible">{{$:/core/images/close-button}}</$button>
+
+</$set>
+
+</div>
+
+</$reveal>
+
+</$list>

editions/tw5.com/tiddlers/filters/haschanged.tid

@@ -0,0 +1,15 @@
+created: 20150208191821000
+modified: 20150208191821000
+tags: [[Filter Operators]] [[Negatable Operators]]
+title: haschanged Operator
+type: text/vnd.tiddlywiki
+caption: haschanged
+op-purpose: returns input titles where the corresponding tiddlers have changed since startup
+op-input: a [[selection of titles|Title Selection]]
+op-parameter: none
+op-output: those input tiddlers that have not changed since startup
+op-neg-output: those input tiddlers that have changed since startup
+
+Each input title is processed in turn, and is returned if any of its fields have changed since startup (or, with negation, if it has not changed).
+
+<<.operator-examples "haschanged">>

themes/tiddlywiki/vanilla/base.tid

@@ -241,6 +241,21 @@ a.tc-tiddlylink-external:hover {
 	content: "<<lingo DropMessage>>";
 }
 
+/*
+** Plugin reload warning
+*/
+
+.tc-plugin-reload-warning {
+	z-index: 1000;
+	display: block;
+	position: fixed;
+	top: 0;
+	left: 0;
+	right: 0;
+	background: <<colour alert-background>>;
+	text-align: center;
+}
+
 /*
 ** Buttons
 */