initial script to create a tuntap interface

Can radvd be tested using tuntab?  Let's find out...
adding tuntap.c

This program dynamically allocates tuntap devices... Maybe we can
allocate a tuntap device, write a config file using the new device
name, then call up radvd...
cleaning up, adding logging
make a dummy tuntap device and advert to it
adding .gitignore
Don't SIOCGIFMTU | SIOCGIFHWADDR in ioctl

When testing with a dummy interface, I found that or'ing together
these values failed to get the device MTU, but doing them each in a
seperate call to ioctl works.
make check
adding check2.c
moving tests to test dir
set_iface_mtu.c works
run radvd test
execv in test
waitpid
add COMMON_SRC to the tests
messing with tests
Attempt to show ALL the hardware device types by name
IFF_TAP tunnels have mac addresses and look like ethernet cards
log the mac address of the ethernet interface
bringing up tap interface
adding a TODO comment