Add a "share app" menu.

[GoogleCodeExporter]

Help users to spread the app.

1. Use the intent to share via (SMS, Mail, Facebook, Twitter ...) with 
default localized text messages.
http://developer.android.com/reference/android/content/Intent.html#ACTION_SE
ND
android.intent.action.SEND

2. Use this intent to display the market QR code: 
com.google.zxing.client.android.SHARE
com.google.zxing.client.android.ENCODE
Info: http://www.openintents.org/en/node/171

Original issue reported on code.google.com by mathieu.mea on 5 May 2010 at 2:37