source rearrangement

I will be rearranging the source, to better fit the plugins and 
other extensions.  There will also be a rearrangement in how it 
is installed.

Old system ...  Basically it is one program.  Installation could 
be just copying the executable to where you want it to be.  In 
my version, "ap_" and "l_" files, and "Make2" and "Make3" were 
symlinked.  For distribution, these were changed to copies of 
files, as per GNU recommendations.

Needed:
Will need to install the core, plugins, tools, and headers.

Installation proposal:
 put it in $(PREFIX)  (likely /usr/share/gnucap)
..../bin - executables: core (gnucap) and tools (modelgen, 
verilog, etc.)
..../lib - plugins - all kinds, regardless of format or 
language, with a local hierarchy. (spice3f5, bsim, core, etc.)
..../include - includes (needed to compile plugins)

Most systems will put this /bin in something 
like /usr/local/bin.  I prefer symlinks.


Splitting the source ...

.../ap
.../core
.../commands (utility)
.../devices
.../analysis commands
.../functions

.../modelgen
.../verilog

.../plugins - place to put the ones that are distributed 
separately.

.../man 
stays the same.


I will do it within a day or so.  comments?