- Fixes the routing problem
  - A new type "sim" has been created but not in the DB. node_types and
    nodes remain unchanged. This will change after we figure out how
    to represent in the DB the local multiple virtnodes in one phynode case
    The frontend tb_compat.tcl adds the sim type and ptopgen associates
    a huge number of sim nodes to all local PCs.
  - All simulated nodes go into one pc untill I finish coding the distributed
    nse case. Also, sim nodes go through assign but with an explicit
    "fix-node" directive in the top file. A random free pc is chosen using
    the avail script in assign_wrapper. If we don't fix node it, assign
    maps sim nodes to multiple phy nodes even when a valid all to one
    mapping is possible.
  - Syntax for nse:

   $ns make-simulated {

       set simnode1 [$ns node]
       set simnode2 [$ns node]

   }
   ...

   The old syntax

   set nsenode [$ns nsenode]
   $nsenode make-simulated {
   }

   is deprecated

  - All 38 frontend ...