remove extraneous explicit unsigned in params (resolves #47)

test/basic/unsigned.sv

@@ -4,4 +4,8 @@ module top;
         for (int unsigned i = 0; i < 4; i++)
             arr[i] = i;
     initial $display(arr);
+
+    parameter unsigned foo = 1;
+    localparam unsigned bar = 1;
+    initial $display(foo, bar);
 endmodule

test/basic/unsigned.v

@@ -6,4 +6,8 @@ module top;
             arr[i] = i;
     end
     initial $display(arr);
+
+    parameter foo = 1;
+    localparam bar = 1;
+    initial $display(foo, bar);
 endmodule