refactor: add test make sbus file

rspower/examples/test_makesbus.txt

+#include ../data/case14.txt
+#include ../lib/idx_gen.txt
+#include ../lib/idx_bus.txt
+#include ../lib/make_sdzip.txt
+#include ../lib/make_sbus.txt
+
+return make_sbus(baseMVA, bus, gen);
\ No newline at end of file

rspower/lib/newtonpf.txt

@@ -66,7 +66,7 @@ fn newtonpf(Ybus, Sbus, V0, ref, pv, pq, mpopt) {
         // dx = linsolve(J, -F);
         dx = J \ -F;
         // update voltage vector
-        V = V + dx';
+        V = V + dx;
 
         F = V .* conj(Ybus * V) - Sbus;
         // check for convergence