Merge pull request #6 from iantocristian/master

peer_id comparison fix
Announce interval can now be passed to the tracker constructor. Default is 30 seconds (as was hard-coded before).
Merge pull request #7 from GlennPorter/master

Announce interval can now be passed to the tracker constructor. Default is 30 seconds (as was hard-coded before).
Set exports.announceInterval with the passed interval.
Merge pull request #8 from GlennPorter/master

Set exports.announceInterval with the passed interval.