This commit includes example tutorials and solutions for P4D2 2017. (#29)

- Added example P4 programs for ipv4_forwarding, mri, arp, calc
- Added python code to invoke compiler, start bmv2, run mininet
- Added solutions to above programs
- Added README files that describe exercises

P4D2_2017/exercises/arp/p4app.json

@@ -0,0 +1,10 @@
+{
+    "program": "arp.p4",
+    "language": "p4-16",
+    "targets": {
+	"mininet": {
+	    "num-hosts": 2,
+	    "switch-config": "simple_router.config"
+	}
+    }
+}