Possible fix for when minecraft refuses to bind to ipv4

Some users were having issues where minecraft would refuse to bind
to ipv4, this is a possible solution to that problem.
Fixed issues with Bukkit support and allow specifying Oracle Java.
Merge branch 'fix-ipv6-issues'

Conflicts:
	attributes/default.rb
Merge pull request #36 from fbrier/master

Bukkit, Oracle Java and gregf IPV4 support