Freerouter Guidelines:
-  in pcbnew, using the Layers Setup dialog:
 - choose the number of layers, and enter the name of each layer.
    These should look something like this (if a 6 layer board):
    - Front - signal
- Ground - power
- H1_Signal - signal
- V2_Signal - signal
- Power - power
- Back - signal
    Notice that after the layer name there is a layer type field, either 'signal' or 'power', typically.
    Any layer identified as 'power' will be removed from the layer menu in Freerouter,
    as this will be assumed to contain a power zone.
-  in pcbnew:  establish board perimeter.
-  in pcbnew: load in the netlist so you have all the components defined and instantiated.
-  in pcbnew: establish any zones, inclusive of net association.
-  in pcbnew: do the degree of component placements you are comfortable with.
     It is a little easier to accurately position components in pcbnew than in
     freerouter, but either will work.
-  in pcbnew: set up the netclasses. Power traces might be a little thicker
     than signal traces. If so, add a netclass called 'power'.
     Make its traces thicker than what you establish for netclass 'Default'.
     Set trace width, spacing and vias for each netclass.
-  in pcbnew: export to DSN.
-  load up freerouter (keep it running for any subsequent iterations of 5) through 16) here).
-  in freerouter: load the project's *.dsn file. Immediately after a load, all
     components and traces (if any) will initially be 'fixed'. This is a 'lock
     in place' toggle that you can undo by selecting a region with your mouse
     and then selecting 'Unfix' from the menu. Occassionally you may want to
     re-fix a trace or a part, if only temporarily. This keeps it locked in
     place.
-  useful, not mandatory: in freerouter: set your move snap modulus, which seems
     to default to 1 internal unit.
     20 mils in x and in y is about reasonable.
-  in freerouter: finish placing any components, you can change sides of a part
     here also, rotate, whatever.
-  in freerouter: route the board, and save frequently to a *.dsn file while
     routing in case of power loss. Pick the menu option for saving a full *.dsn
     file, not a session file (yet). The full freerouter *.dsn file is a superset
     format, one that can be reloaded in the event of a power loss. Whereas the
     *.ses file is not a complete design, but only with the *.brd file
     constitutes a full design. So it is important to backup your work to a
     *.dsn file while routing in case of power loss.
-  in freerouter: when done, or when you want to back import, then save as a session file, *.ses.
-  in pcbnew: backimport the session file
-  in pcbnew: at this point the zones have to be refilled. One way to do that
     is to simply run DRC.