add veth8 platform

Like the default eth platform, but uses 8 veths pairs instead of 4.
diff --git a/platforms/veth8.py b/platforms/veth8.py
new file mode 100644
index 0000000..5d7ec5a
--- /dev/null
+++ b/platforms/veth8.py
@@ -0,0 +1,23 @@
+"""
+veth8 platform
+
+This platform uses 8 veth pairs. The switch should connect to veth0, veth2, ..., veth14.
+"""
+
+def platform_config_update(config):
+    """
+    Update configuration for the local platform
+
+    @param config The configuration dictionary to use/update
+    """
+
+    config['port_map'] = {
+        1: 'veth1',
+        2: 'veth3',
+        3: 'veth5',
+        4: 'veth7',
+        5: 'veth9',
+        6: 'veth11',
+        7: 'veth13',
+        8: 'veth15',
+    }