Extend package name with class name

Android activities can use the same package name as other activities
when they are related. Specially when they are launched from the same
application.

Therefore, to differenciate these activities, use "flattenToString"
method that returns an extended package name with the activity class
name.

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>
Release 1.18

Signed-off-by: Martin Abente Lahaye <tch@sugarlabs.org>