Bunch of small updates

Great work guys, as always! :)

Updates as follow:

app/index.html

+ Add Google publisher/ownership meta tag
+ ico/png favicon appropriate support for IE and other browsers
+ Add robots meta tags
+ Add Facebook Open Graph
+ Add Twitter Summary Card
+ Add optional Twitter app integration tags

Images:

+ Add app/images/thumbnail-1024x1024.png, app/images/thumbnail-1024x1024.jpg, app/images/favicon.png
+ Move app/favicon.ico to app/images/favicon.ico so to match with above favicon update