updating Dia scripts to parse imgmap in Dia.pm

Things we needed:

1. Pass the filename to Dia so we can chop it and make it fname.png.
2. Pass the parsed urls into Dia so we can use them when we're
generating the map.

Using /usr/share/dia/python/imgmap.py to figure out how to make an
imgmap.
checking in with broken imgmap code

Checking this in for reference.  The comments are in the source as to
how I might want to fix it.

We're doing some semi-lowlevel dia crap to get this to work.  Arguably
it should be written into a standalone Dia class so others could make
use of it, but I don't feel like I'm doing enough with it to make it
worth anyone elses time.

If we start doing more dia then I may fork that off into it's own
module.
Another comment before changing code
small fixes to usage2dia

made usage an int because it won't be postprocessed into one since we're
doing the imgmap here.

change it so if mdate ne $dia->mtime then reinit variables because dia
file changed.

chomp the last line of output to suppress final \n
more changes for dia
changed connections to dynamic lookup

now just need to setup the polygon mapping for imgmaps and it should be
done