Improve "mdp ping" command

Packet stats now exclude duplicate pong replies

With <count> arg, exits immediately once a pong has been received for
every ping, unless new --wait-for-duplicates option given

Routing tests for unreliable links now assert all pongs received and
very few duplicates
Refactor and move logArgv() to log_util.c
Move console reading from vomp_console.c to console.c
Minor refactoring
Start building a new AF_UNIX based network simulator
Rework simulator to use console.o
Add network reliability filters and overall rate limiting to simulator