chore(example): remove example file and add links

examples/README.md

 ## Example plugin implementations
 
-datasource:[simple-json-datasource](https://github.com/grafana/simple-json-datasource)
-app:  [example-app](https://github.com/grafana/example-app)
\ No newline at end of file
+datasource:[simple-json-datasource](https://github.com/grafana/grafana-simple-json-datasource)
+app:  [example-app](https://github.com/grafana/grafana-example-app)
+panel: [grafana-piechart-panel](https://github.com/grafana/piechart-panel)

examples/boilerplate-es5-panel/css/styles.css

-.panel-boilerplate-values {
-  text-align: center;
-}
\ No newline at end of file

examples/boilerplate-es5-panel/module.js

-define([
-  'app/plugins/sdk',
-  'lodash',
-  './css/styles.css!'
-], function(sdk, _) {
-
-  var BoilerPlatePanelCtrl = (function(_super) {
-    var self;
-
-    function BoilerPlatePanelCtrl($scope, $injector) {
-      _super.call(this, $scope, $injector);
-
-      this.results = []
-
-      self = this;
-    }
-
-    // you do not need a templateUrl,  you can use a inline template here
-    // BoilerPlatePanelCtrl.template = '<h2>boilerplate</h2>';
-
-    // all panel static assets can be accessed via 'public/plugins/<plugin-id>/<file>
-    BoilerPlatePanelCtrl.templateUrl = 'panel.html';
-
-    BoilerPlatePanelCtrl.prototype = Object.create(_super.prototype);
-    BoilerPlatePanelCtrl.prototype.constructor = BoilerPlatePanelCtrl;
-
-    BoilerPlatePanelCtrl.prototype.refreshData = function(datasource) {
-      this.issueQueries(datasource)
-        .then(function(result) {
-          self.results = [];
-          _.each(result.data, function(target) {
-            var last = _.last(target.datapoints)
-            self.results.push(last[0]);
-          });
-
-          self.render();
-        });
-    }
-
-    BoilerPlatePanelCtrl.prototype.render = function() {
-      this.values = this.results.join(',');
-    }
-
-    return BoilerPlatePanelCtrl;
-
-  })(sdk.MetricsPanelCtrl);
-
-
-  return {
-    PanelCtrl: BoilerPlatePanelCtrl
-  };
-});
-

examples/boilerplate-es5-panel/panel.html

-<h2 class="text-center">
-	Basic panel
-</h2>
-
-<p class="panel-boilerplate-values">{{ctrl.values}}</p>
-
-

examples/boilerplate-es5-panel/plugin.json

-{
-  "type": "panel",
-  "name": "Panel Boilerplate",
-  "id": "panel-boilerplate-es5",
-  "staticRoot": "."
-}