IPV6 testing & minor changes and fixes

IPV6 testing & minor changes and fixes

IPV6 test has been added. The generator will now generate IPV6 packets
using NDP to resolve MAC addresses. The hex IP addresses in the inline
definition of the packets in the cfg files is now calculated by a lua
function called in parameters.lua. The hard-coded path /home/centos has
been replaced by ~. An error in the speed calculations has been fixed.
See the RapidTest class for details. The actual number of generated
flows is now reported. If the requested number of flows is not a power
of 2, the lowest power of 2 that is larger than the requested number of
flows will be used and reported.

Change-Id: I36b8d345b4a03c2cf358c19ec353ca8ad2831293
Signed-off-by: Luc Provoost <luc.provoost@intel.com>