* Added Makefile and topology.jsons for all examples.
* use branch
* Updated MRI exercise (#73)
* Updated MRI exercise
* Updated basic_tunnel.p4 for changes to p4 lang
* updated other examples
* 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.