in section.C:

  Section::draw() was changed to make frozen track (at an accident) flash
  as a zigzag instead of a line segment.  If the section's frozenStatus
  is true, a zigzag is drawn.  Otherwise, a line segment is drawn.

  Immediately above Section::draw(), two #defines are added.

in platform.h:

  Added to the Platform class a one-line public function that returns
  the track section adjacent to the platform (used for accidents):

      Section *adjSection()  { return section; }

in events.C:

  Defined MEAN_ACCIDENT_DURATION and TIME_BETWEEN_ACCIDENTS (you should use
  different values, which are defined in the assignment).   Added some 
  #include files.

in train.C:

  Added some code in the `else' clause with comment

     // If arriving at platform, stop in centre of track section

  in order to have trains go at yellow speed until they have half
  a train length remaining before stopping.  Otherwise, trains
  that stop outside a station will be too slow upon entering it.

in controller.C:

  Removed some tests from Controller::trainIsLeavingSection() for
  !s->frozenStatus.  These were preventing the track status from
  being set correctly to one side of an accident.  

  Removed similar tests in Controller::trainIsReversing().

in main.C and main.h:

  Added a variable

    bool allowAccidents = true;

  If false, accidents don't occur and the arrival times you get
  (without accidents) should be identical to the arrival times of this
  program.  If accidents are allowed, the sequence of random numbers
  used for arrival times is different and your arrival times will be
  different from those of this program.  You MUST NOT implement this
  flag in your own code.

in main.C:

  Added  #include "statistics.h"

in main.h

  Remove some #includes and replaced them with class prototypes.

in options.C:

  Added code to have -A option change the state of allowAccidents.

in statistics.h:

  Added some #includes.
  Defined MAX_NUM_STATIONS that you should use to set up arrays
    to collect statistics about stations.  Ideally, the statistics
    instance should be created *after* the number of stations is
    known (after setupNetwork()), but I'll use the MAX_NUM_STATIONS
    hack to avoid modifying code that you might already have
    worked on.  You may assume that there will never be more than
    MAX_NUM_STATIONS stations.  No error checking is necessary.

in station.h:

  Added "friend class Statistics" to Station class in order that
  Statistics has access to the station index.

in station.C:

  Added some #includes.

in scheduler.C:

  Added #include "statistics.h".

