This will ultimately be a member of a list of descriptors and
their handler functions on which we need to select() in the
main loop.
o Make struct physical into a `sort' of struct descriptor.
This structure will eventually contain a list of NCPs (currently
only IPCP is supported) and a list of physical `struct link's.
It will also derive from a struct link itself.
Make ModemTimeout() static - it's way to dangerous to be called
from outside !
Bump version to 1.9. Our first MP release should be 2.0.