Added extra benchmark models.

tests/benchmarking/bench_300x300x300.in

@@ -0,0 +1,7 @@
+#domain: 0.3 0.3 0.3
+#dx_dy_dz: 0.001 0.001 0.001
+#time_window: 3e-9
+
+#waveform: gaussiandotnorm 1 900e6 MySource
+#hertzian_dipole: x 0.05 0.05 0.05 MySource
+#rx: 0.05 0.05 0.05

tests/benchmarking/bench_400x400x400.in

@@ -0,0 +1,7 @@
+#domain: 0.4 0.4 0.4
+#dx_dy_dz: 0.001 0.001 0.001
+#time_window: 3e-9
+
+#waveform: gaussiandotnorm 1 900e6 MySource
+#hertzian_dipole: x 0.05 0.05 0.05 MySource
+#rx: 0.05 0.05 0.05