Issue #9: Added VectorPrinter

Helper class to print vectors of various objects. The print() method is
overloaded for vectors of Course, Prof, and Room objects; a second
parameter allows clients to use the method to print to any output
stream. (Default is std::cout.)
Issue #9: Reader classes now use VectorPrinter

Now that I wrote the VectorPrinter class, I actually had the other test
classes use it. Makes the code much simpler.
Issue #9: Modified component names in tests

Tests should say which component they're testing (e.g. "Rooms"), not
which test class they are (e.g. "TestRooms").