Fix-ups for next NDT package

These are the fixes for the next public, m-lab packaged version of NDT.

Primary changes:
 * use 3.6.4-3.6.4.2 version in SVN rather than the published 3.6.4 package
 * add support for jar signing for a future release (changing java package version)
 * add web100-pcap patch to fix DNS "reverse-lookup" bug.