[Gpsbabel-code] New DeLorme stuff

[Ron P. <ro...@pa...>]

I have added a few new options to the Street Atlas formats, and documented
one old option.  This is all in service of solving a long-standing problem
with the various DeLorme products, which is that it's impossible to draw a
routable road that intersects with a limited-access or toll highway.

The first option, usable for all kinds of mischief, is the "split" option
for saroute.  This creates a new route at each turn, allowing one to separate
out just one street if one had a use for that.  In addition, splitting by
street allows us to use the street names for route names.

The other new options are for the an1 format.  They're documented in README,
but the short story is that they're usable for creating and making some
very specific but very interesting changes to routable road layers.  Being
able to split by turns in saroute helps here, in that it allows one to easily
create a routable road that exactly follows the path of an existing road 
between
two intersections.

Another an1 change is that when writing to a road layer, we now use the route
name for the road name.  Funny how that works in conjunction with saroute's new
split option, isn't it?