Initial Commit based on Google Mirror Quick Start

This commit is a simple copy from the google mirror
quick start project.
setting the configuration for mirroremul webapp
update index.jsp for emulated version
Adding utility class to retrieve application URL

First implementation of the way to retrieve the app engine
application URL that host the scarygami/emulator
Adding support to retrieve Mirror from emul API
Adding support for the welcome message

Du to the open source quick start , we provide a way to custome
the welcome message. Like that each tester can provide their own message
to ensure the test.
Ensure to avoid an exception during bootstraping
adding scope for userinfo.email
adding support for attachment
error with url
adding dependency for java-mirror-api-emulated