Updates for p4runtime example (#71)

* Created p4runtime exercise directory with draft P4 program

* Updating VM

- Adding p4 to vboxsf group for VirtualBox Shared Folders
- Adding gRPC Python package for p4 runtime
- Setting up VM to use 2 CPUs

* Updating .gitignore for PyCharms and Mac OS

* Adding P4RuntimeSwitch type and support in run_exercises

If the grpc switch target is used, we will instantiate a P4RuntimeSwitch.
Ideally, this will get merged with BMv2's P4Switch and can be removed

* Adding p4 runtime and p4info browser libraries

Also, adding a Makefile for this project

P4D2_2017_Fall/vm/user-bootstrap.sh

@@ -45,6 +45,8 @@ sudo make install
 sudo ldconfig
 unset LDFLAGS
 cd ..
+# Install gRPC Python Package
+sudo pip install grpcio
 
 # BMv2 deps (needed by PI)
 git clone https://github.com/p4lang/behavioral-model.git