Fix filename in header comment.
Add Connector class with tests, harden Makefile dependencies.

o Add tests and runtests Makefile targets
o Tweak Makefile targets to harden dependency checking
o Add Connector class which creates and closes a socket
o Add support for Doxygen documentation
o Add CppUnit-based unit tests for the Connector class
Add Doxygen support, create documentation during build.
Ignore generated directories.