Basic Encapsulation Example (#64)

* Adding initial implementation of basic_encap example

* Updated basic_encap example to count the number of valid packets

* Updated basic_encap example to put encapsulation layer after Ethernet
header.

* Added solution file for basic_encap example

* Changed the name of the basic_encap example to basic_tunnel and called
the new header myTunnel. Also changed the myTunnel field names slightly.

P4D2_2017_Fall/exercises/basic_tunnel/p4app.json

@@ -0,0 +1,32 @@
+{
+    "program": "basic_tunnel.p4",
+    "language": "p4-16",
+    "targets": {
+      "multiswitch": {
+          "auto-control-plane": true,
+          "cli": true,
+          "pcap_dump": true,
+          "bmv2_log": true,
+          "links": [["h1", "s1"], ["s1", "s2"], ["s1", "s3"], ["s3", "s2"], ["s2", "h2"], ["s3", "h3"]],
+          "hosts": {
+            "h1": {
+            },
+            "h2": {
+            },
+            "h3": {
+            }
+          },
+          "switches": {
+              "s1": {
+                  "entries": "s1-commands.txt"
+              },
+              "s2": {
+                  "entries": "s2-commands.txt"
+              },
+              "s3": {
+                  "entries": "s3-commands.txt"
+              }
+          }
+	    }
+    }
+}