Added spinit file under custom/models to get the correct startup
options for ngspice.  Made a "create_project" script to create some
basic project subdirectories and seed them with links to the
appropriate startup files.  Modified the "preproc" script so that
it maintains the file permissions from input to output.
diff --git a/Makefile.in b/Makefile.in
index ac398c8..a98af99 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -80,11 +80,15 @@
 
 #---------------------------------------------------
 
+CPP = common/preproc.py
+
 common_install:
 	mkdir -p @prefix@/pdk/bin/
 	cp common/cleanup_unref.py @prefix@/pdk/bin/
 	cp common/soc_floorplanner.py @prefix@/pdk/bin/
-
+	${CPP} -DPREFIX=@prefix@ common/create_project.py \
+		@prefix@/pdk/bin/create_project.py
+	
 #---------------------------------------------------
 
 tech_sky130: