Fixed sorting issue caused by concurrency and JDK7
Merge branch 'rare-torrent-bonus' of https://github.com/PritomAhmed/bittorrentsim-java into rare-torrent-bonus

Conflicts:
	.idea/workspace.xml
	out/production/BittorrentSim/Main.class
	out/production/BittorrentSim/Peer.class
	out/production/BittorrentSim/Tracker.class
	src/SharedFile.java
Experiment of bonus for seeding rare files carried out