Network and address pool (again)

Implementation of the network objects and address pool. Functionality
as in the reverted commit b9a616e1, but
now using only the vector library and not the bit-vector library.
Tested with vector library version 0.9 and 0.10., which are
also installed on the buildbot machines now.

Signed-off-by: Helga Velroyen <helgav@google.com>
Reviewed-by: Iustin Pop <iustin@google.com>