Fixed small problems in the README

Added the text describing how to run the subscriber application.
Fixed small typo in the README
One more fix to the topmost README
Adding C example, update C++

Minor fix to the comments in the C++ example, and updated the comments
in the C++ subscriber cxx file.
Merge pull request #5 from rosemwahlin/master

I fixed the README text in a few places, and created the C example.