* ptopgen:

   1. Change to using interface_capabilities table to get the default
      speed for an interface type.

   2. The wrinkle is that an interface can have multiple speeds,
      depending on the protocol that is requested. In the wireless case the
      table looks like:

	| type             | capkey            | capval               |
	+------------------+-------------------+----------------------+
	| ath              | protocols         | 80211a,80211b,80211g |
	| ath              | 80211a_defspeed   | 54000                |
	| ath              | 80211b_defspeed   | 11000                |
	| ath              | 80211g_defspeed   | 54000                |

   3. We use the above info to tell us the default speed for links, based
      on the particular protocol.

   4. And lastly, create "air" switches for each of 80211a, 80211b, 80211g,
      and specify links from the switches to the nodes that have interfaces
      that support those protocols. At the moment, there is a hardwired
      list of 80211a, 80211b, 80211g in ptopgen, so create 3 new air
      switches and links from each of the nodes to each of the switches.
      Rob says that assign can handle this just fine (using the same
      interface on a node to connect to three different air switches, at
      different speeds).

* assign_wrapper:

   1. First off, I had to increase the bogousity factor of how we determine
      that a delay node is required (requires_delay() routine) on a link or
      lan. Using the interface_capabilities table, I determine the default
      speed for each protocol on each interface type.

   2. When calling requires_delay() I now the pass the lan so that we can
      get the "protocol" of the link/lan and use that to find the default
      speed. The main reason for all this crud is that if a user specifies
      a bandwidth of 54Mb on a wired ethernet, we want to make sure we
      insert a delay node, but not if the user is using 80211g. As it was,
      delay nodes would be skipped cause there are now nodes with
      interfaces that support those speeds. This change also allows to know
      that a delay node should be inserted on a wireless link, if we ever
      wanted to do something as silly as that!

   3. Okay, so now onto the actual wireless support!  Whenever the protocol
      for a lan is not "ethernet" spit out links to fake lan nodes, sorta
      like we used to do with ethernet lans before Rob made all those great
      changes to assign. So, a lan with protocol 80211a will get fake links
      to the 80211a air switch that ptopgen spits out (see above).  We
      currently bypass all delay node processing on wireless lans, and in
      fact we avoid most post-processing (after assign) of wireless lans
      (no vlans, veths, etc). At some point we can bring certain things
      back in (like emulated links) but that will be some time! See
      comments above about ptopgen.

   4. Added a section to copy over the virt_lan_settings and
      virt_lan_member_settings to the interface_settings table, for each
      node's interfaces in the mapped experiment. I also make up the ssid
      for the lan, and add the protocol to the settings so that the client
      side knows what it is supposed to do. I also set the acesspoint since
      that requires MAC addresses, and this is easiest place to get and set
      the MAC (all of the nodes in a lan need to know the MAC of the node
      acting as the access point). In the virtual topology, the accesspoint
      is specified as a node name.

* tbsetup/ns2ir:

   1. Add tb-set-lan-protocol(lan, protocol) to set the protocol to one of
      ethernet, 80211a, 80211b, 80211g. Defaults to ethernet.

   2. Add tb-set-lan-accesspoint(lan, accesspoint) to set the name of the
      access point for a lan. Obviously this makes sense for only wireless
      links; ignored for wired links.

   3. Add tb-set-lan-setting(lan, setting, value) to specify a setting that
      applies to the entire lan. At present, these are ignored for wired
      lans. Both setting and value are strings.

   4. Add tb-set-node-lan-setting(lan, node, setting, value) to specify a
      setting that applies to a particular node in a lan. At present, these
      are ignored for wired lans. Both setting and value are strings.