[#69] Moved some classes from core.helpers up to core.

git-svn-id: http://svn.code.sf.net/p/jbidibc/code@895 87107999-b52a-42af-a34b-1e85ba8a0939
Fixed NPE if no listeners are available.

git-svn-id: http://svn.code.sf.net/p/jbidibc/code@896 87107999-b52a-42af-a34b-1e85ba8a0939