Travel Constraints Menu and Empty Map.h Implementations

Just added a switch case with a description of each of the methods (if we need it ?), and the empty implementations of the travel Contraints menu. Currently the while() loop for the Travel Menu terminates with !isdigit(). But I don't know if that is the proper way to terminate the loop.  

Things needed-
*Have all the empty methods take in the necessary parameters (J,S,C,etc..), but do nothing with them
*Print out the entire flight schedule in the "P" option.