we have liftoff - lisp code still needs fixing

ctree/ortree/sigbuf all tests working

test/unit_tests/sigbuf_15/run/prsim.out

@@ -0,0 +1,3 @@
+t.sigbuf_test.buf6._y t.in t.out 
+0
+1

test/unit_tests/sigbuf_15/run/test.prs

@@ -0,0 +1,14 @@
+= "GND" "GND"
+= "Vdd" "Vdd"
+"t.sigbuf_test.buf6.a"->"t.sigbuf_test.buf6._y"-
+~("t.sigbuf_test.buf6.a")->"t.sigbuf_test.buf6._y"+
+"t.sigbuf_test.buf6._y"->"t.sigbuf_test.buf6.y"-
+~("t.sigbuf_test.buf6._y")->"t.sigbuf_test.buf6.y"+
+= "t.sigbuf_test.supply.vdd" "t.sigbuf_test.buf6.vdd"
+= "t.sigbuf_test.supply.vss" "t.sigbuf_test.buf6.vss"
+= "t.sigbuf_test.out" "t.sigbuf_test.buf6.y"
+= "t.sigbuf_test.in" "t.sigbuf_test.buf6.a"
+= "Vdd" "t.sigbuf_test.supply.vdd"
+= "GND" "t.sigbuf_test.supply.vss"
+= "t.out" "t.sigbuf_test.out"
+= "t.in" "t.sigbuf_test.in"