chore(demo): demo site and readme additions/fixes

* fix github link in navbar
* add version and github stats to readme

Closes ng-bootstrap#537

Author: icfantv

README.md

@@ -1,11 +1,14 @@
 # NG Bootstrap - [Angular 2](http://angular.io/) directives specific to [Bootstrap 4](http://v4-alpha.getbootstrap.com/)
 
+[![npm version](https://badge.fury.io/js/%40ng-bootstrap%2Fng-bootstrap.svg)](https://badge.fury.io/js/%40ng-bootstrap%2Fng-bootstrap)
 [![Build Status](https://travis-ci.org/ng-bootstrap/ng-bootstrap.svg?branch=master)](https://travis-ci.org/ng-bootstrap/ng-bootstrap)
 [![devDependency Status](https://david-dm.org/ng-bootstrap/ng-bootstrap/dev-status.svg?branch=master)](https://david-dm.org/ng-bootstrap/ng-bootstrap#info=devDependencies)
+[![Issue Stats](http://issuestats.com/github/ng-bootstrap/ng-bootstrap/badge/pr)](http://issuestats.com/github/ng-bootstrap/ng-bootstrap)
+[![Issue Stats](http://issuestats.com/github/ng-bootstrap/ng-bootstrap/badge/issue)](http://issuestats.com/github/ng-bootstrap/ng-bootstrap)
 
 Welcome to the Angular 2 version of the [Angular UI Bootstrap](https://github.com/angular-ui/bootstrap) library.
 This library is being built from scratch by the [ui-bootstrap team](https://github.com/angular-ui/bootstrap).
-We are using TypeScript and targeting the Bootstrap 4 CSS framework. 
+We are using TypeScript and targeting the Bootstrap 4 CSS framework.
 
 As with Bootstrap 4 and Angular 2, this library is a work in progress. Please check out our list of
 [issues](https://github.com/ng-bootstrap/ng-bootstrap/issues) to see all the things we are implementing.

demo/src/app/app.component.html

@@ -22,8 +22,7 @@
           <svg aria-hidden="true" class="octicon octicon-mark-github" height="28" version="1.1" viewBox="0 0 16 16"
             width="28">
             <path d="M8 0C3.58 0 0 3.58 0 8c0 3.54 2.29 6.53 5.47 7.59.4.07.55-.17.55-.38 0-.19-.01-.82-.01-1.49-2.01.37-2.53-.49-2.69-.94-.09-.23-.48-.94-.82-1.13-.28-.15-.68-.52-.01-.53.63-.01 1.08.58 1.23.82.72 1.21 1.87.87 2.33.66.07-.52.28-.87.51-1.07-1.78-.2-3.64-.89-3.64-3.95 0-.87.31-1.59.82-2.15-.08-.2-.36-1.02.08-2.12 0 0 .67-.21 2.2.82.64-.18 1.32-.27 2-.27.68 0 1.36.09 2 .27 1.53-1.04 2.2-.82 2.2-.82.44 1.1.16 1.92.08 2.12.51.56.82 1.27.82 2.15 0 3.07-1.87 3.75-3.65 3.95.29.25.54.73.54 1.48 0 1.07-.01 1.93-.01 2.2 0 .21.15.46.55.38A8.013 8.013 0 0 0 16 8c0-4.42-3.58-8-8-8z"></path>
-          </svg>
-        </a>
+          </svg></a>
         <a class="github-button"
            href="https://github.com/ng-bootstrap/ng-bootstrap"
            target="_blank"