Adds mailto link for sharing by email
Implements an other way to get the Google+ Button in the App-Bootstrap
Merge branch 'fix/google-plus'

* fix/google-plus:
  Implements an other way to get the Google+ Button in the App-Bootstrap
  Adds mailto link for sharing by email

Conflicts:
	src/ch/uzh/ifi/se/yapp/facade/gwt/client/ApplicationBootstrap.java