and generate the table of stuff to register from tap source files, so
Tethereal doesn't need to know what tap listeners exist.
Get rid of "tap-xxx.h" files, as they're now empty.
Add "tethereal-tap-register.c" to the .cvsignore file, as it's a new
generated file.
Update "Makefile.nmake" to generate "tethereal-tap-register.c".
Clean up "Makefile.am" and "Makefile.nmake" a bit.
svn path=/trunk/; revision=6525