arp_cache vtable for OSX and Linux

This is a cleanup and merge of the ARP cache table into routes for OSX. 
* arp_cache is a more appropriate name than arp/arp_table.
* Rename `canonical_X_address` to `ipAsString`, `macAsString`.
* Improve provisioning on Linux when building from a VMware SF mount.
* Fix trailing ":" for MAC address displays.
* Fix /32 netmask for IPv6 routes on OSX.