MSA-1559: Trend Setter is a SmartApp for grouping together devices for synchronised control and/or data aggregation using virtual devices that act as a controller device and interface for other devices in the group. At present there are 4 group types:

Switch - Group switch control
Dimmer - Group level/switch control
Colorful Light - Group colour/level/switch control
Power Meter - Averaged total power usage for group with High/Medium/Low usage indicator based on previous data (Experimental, possibly very inaccurate)

More information is better found here:
https://community.smartthings.com/t/release-trend-setter/31286

The SmartApp seems to be quite popular now so I thought I would submit it for publication as some people aren't keen on having to install multiple SmartApps and Device Handlers.

smartapps/kriskit-trendsetter/trend-setter.src/trend-setter.groovy

@@ -0,0 +1,58 @@
+/**
+ *  Trend Setter
+ *
+ *  Copyright 2015 Chris Kitch
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ *  in compliance with the License. You may obtain a copy of the License at:
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software distributed under the License is distributed
+ *  on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License
+ *  for the specific language governing permissions and limitations under the License.
+ *
+ */
+definition(
+    name: "Trend Setter",
+    namespace: "kriskit.trendSetter",
+    author: "Chris Kitch",
+    description: "Uses virtual child devices to group other devices together and perform commands and aggregate data from the group.",
+    category: "My Apps",
+    iconUrl: "https://cdn.rawgit.com/Kriskit/SmartThingsPublic/master/smartapps/kriskit/trendsetter/icon.png",
+    iconX2Url: "https://cdn.rawgit.com/Kriskit/SmartThingsPublic/master/smartapps/kriskit/trendsetter/icon@2x.png",
+    iconX3Url: "https://cdn.rawgit.com/Kriskit/SmartThingsPublic/master/smartapps/kriskit/trendsetter/icon@3x.png",
+    singleInstance: true)
+
+
+preferences {
+    page(name: "mainPage")
+}
+
+def mainPage() {
+	dynamicPage(name: "mainPage", title: "Your Groups", install: true, uninstall: true, submitOnChange: true) {
+        section {
+        	app(name: "groups", appName: "Group", namespace: "kriskit.trendSetter", title: "Create Group...", multiple: true)
+        }
+    }
+}
+
+def installed() {
+	log.debug "Installed with settings: ${settings}"
+
+	initialize()
+}
+
+def updated() {
+	log.debug "Updated with settings: ${settings}"
+
+	unsubscribe()
+	initialize()
+}
+
+def initialize() {
+	// TODO: subscribe to attributes, devices, locations, etc.
+}
+
+def childUninstalled() {
+}