Make Jitsi-Hammer callable from Jitsi when using username/password (WIP).
Add overall stats computed from ALL the stats collected during the run.
Make the shutdown clean by adding a shutdown hook that correctly
stop the hammer (correctly write the stats files, even if "length" wasn't given).
Merge branch 'master' of https://github.com/jitsi/jitsi-hammer

Conflicts:
	src/org/jitsi/hammer/Main.java