Update install-p4-tools.sh to use P4Runtime v1.0

Includes also various improvements to the p4vm scripts, such as:
- Choose to build VM with Ubuntu 16.04 or 18.04 (experimental)
- Allow users to specify version of protobuf and grpc to use
- Avoid building protobuf and grpc if already installed in the system
- Install Bazel 0.22

Also:
- Remove check for invalid group member weights (now PI always returns
members with weight 1)
- Re-compiled all P4 programs and fixed missing padding in controller
packet headers

Change-Id: I0e672fcebbaba63354c749f0c774af251f3cbc6c
diff --git a/apps/p4-tutorial/pipeconf/src/main/resources/mytunnel.p4 b/apps/p4-tutorial/pipeconf/src/main/resources/mytunnel.p4
index 36de752..f88f582 100644
--- a/apps/p4-tutorial/pipeconf/src/main/resources/mytunnel.p4
+++ b/apps/p4-tutorial/pipeconf/src/main/resources/mytunnel.p4
@@ -69,6 +69,7 @@
 @controller_header("packet_in")
 header packet_in_header_t {
     bit<9> ingress_port;
+    bit<7> _padding;
 }
 
 // Packet-out header. Prepended to packets received by the controller and used
@@ -76,6 +77,7 @@
 @controller_header("packet_out")
 header packet_out_header_t {
     bit<9> egress_port;
+    bit<7> _padding;
 }
 
 // For convenience we collect all headers under the same struct.