Add CustomTimer and separate left/right leg handling

Imported from the unarchived 'hexapod' sketch folder. The real date of this
version is unknown; file dates were lost in a 2016-11-14 copy.

2012-simulation/processing-3d/hexapod/CustomTimer.pde

@@ -0,0 +1,19 @@
+class CustomTimer
+{
+  int time;
+  boolean start=true;
+  public boolean delay(int delay)
+  {
+    if (start)
+    {
+      time = millis();
+      start = false;
+    }
+    if (millis() - time >= delay)
+    {
+      start = true;
+      return true;
+    } else
+      return false;
+  }
+}