Fixed #26: implemented ReaderFactory factories.

ReaderFactory is the pure virtual base class for a factory that will generate vectors of Course, Prof, and Room objects. FileReaderFactory is a concrete implementation that reads this data from files. (Other classes could read from things like databases, REST website calls, or whatever.)

Sample usage:

ReaderFactory* factory = new FileReaderFactory(); // delimiter = comma
vector<Course> courses = factory->getCourses("filename1.csv");
vector<Prof> profs = factory->getProfs("filename2.csv");
vector<Room> rooms = factory->getRooms("filename3.csv");
delete factory;