Many changes to Location service behaviour.
Service can now be started by pressing button in MainActivity view.
Service is independent from app itself and can "live" even after exiting
app. If the user does not stop service manualy then during next app
entry MainActivity will bind to service to gether location updates
automatically.
Other views can also bind to service by using special method in service
and passing their method to be invoked when new location becomes
available. 
WARNING! There is potential problem with Thread concurency when
(un)registering activity for location updates. It is possible that
thread updating location will try to invoke method that is being removed
from list of methods. In this case exception will be raised and catched
immediately after this method. I'm currently looking for any better
solution for this problem.