Set unit testing with gtest/ctest.

Running "make" will now generate test drivers, and running "make test" will
run the test drivers.  New unit tests are meant to be added to the same
directory as the source file which they are testing using a .test.cpp
extension.  For now, there is a single unit test which forces a fail.
There are other commented out tests in CardSet.test.cpp which describe new
feature development.  Also, there is some refactoring work being done in
pscolex/main.cpp.
Merge branch 'master' of https://github.com/andrewprock/pokerstove