Added "view" suppport.

scad-views.scad

@@ -0,0 +1,11 @@
+
+module display(view) {
+  $sc_view=view;
+  children();
+}
+
+module view(view) {
+  if($sc_view == undef || $sc_view == view) {
+    children();
+  }
+}

scad-views.test.scad

@@ -0,0 +1,17 @@
+use <scad-common.scad>;
+use <scad-views.scad>;
+
+// View
+View=0; // [0:all,1:front,2:side,3:top]
+
+module test() {
+    view("front") rotate([90,0,0]) color("blue") square(10,10);
+    view("side") rotate([0,-90,0]) color("red") square(10,10);
+    view("top") square(10,10);
+}
+
+v_arr=[undef,"front","side","top"];
+display(v_arr[View]) {
+    test();
+    move(x=20) test();
+}