Refactored the constants in the launcher for better sharing.
I worry about the hard coded file separator there (/),
so replaced in the code, but left the constant in,
in case someone was using it.
Updated WHATSNEW. Added which.jar to the fetchables.
git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@277559 13f79535-47bb-0310-9956-ffa450edef68