iperf_self: use new Ipaddr.V4.to_string function
Fix block_perf

There's no need to have an IP address for a block throughput example/test
Fix io_page
Add the ping example

It already built without problems.
Add tcp to the Makefile
Update mirage_guest_agent to the new xenstore interface
Add the suspend example to the Makefile
Fix static_website
Update README.md
Update .gitignore
Some of the examples only build on xen: adjust Makefile to cope

We should enhance the base mirage platform so that these (or similar)
examples work.
[make] add lwt targets
[lwt] add first challenge code and conf
[lwt] add second challenge code and conf
[lwt] rename to match tutorial wiki page
[lwt] more sensible  names
[lwt] stop ignoring makefile, plus eg.3
[lwt] complete all examples from wiki Lwt tutorial
[make] cleanup more droppings
[basic] portable console.log rather than print_endline