mini-ndn

At least one user (and myself) have been able to observe significant issues with reported ndnping RTTs when using VirtualBox on a Windows host system; these issues are not observed with Ubuntu or up-to-date versions of VMWare Desktop on the same hardware. Both systems are using a an AMD Ryzen CPU; it's unclear if this can be replicated on Intel given my resources. This should be documented in the README, and ideally we should try to better understand the scope of the issues.