/* Dr. Necro 
   By: Ken Schafer
       ported and polished from an original GFA Basic program


   C_0.40 -- 11/11/94
   ------------------
   My, how time flies.
   Just a maintenance release for the demanding public. =)
   Added a pause key.

   C_0.35 -- 6/18/93
   -----------------
   Much fine-tuning... animation is twice as fast.  Working on high
   score routines.

   C_0.34 -- 4/18/93
   -----------------
   Added interleaved wipe routine.
   Removed the evil sprintf's.

   C_0.33 -- 3/8/93
   ----------------
   Added more sound effects, turned on background music code.

   C_0.32 -- 3/3/93
   ----------------
   Restructured main loop, preparations for background music,
   Addition of 'score numbers' for killed viruses.
   More little 'cleanup' type things.

   C_0.31 -- 2/25/93
   -----------------
   Brand new line check and pill drop routines, fix the 'drive by shooting'
	 problem!  Some miscellaneous cosmetic fixes, and code clean-up.
   New artwork by none other than Adrean Zee, cleaned up by me.

   C_0.30 -- 1/23/92
   -----------------
   Installing sample playback routines.

   C_0.28 -- 12/26/92
   ------------------
   Installed new bitblock copy routines -- incredible increase in speed.
   Interrupt animation works wonderfully.

   C_0.27 -- 8/19/92
   -----------------
   added virus routines, scoring and display
   with the exception of animation and music, this is identical to GFA 0.62a

   C_0.26 -- 8/16/92
   -----------------
   conversion to GFA 0.62a logic.

   C_0.25 -- 8/14/92
   -----------------
   pill shapes nearly complete.

   GFA Ver 0.62     8/6/92
   -------------------
   New concept for virus animations.  Viruses are animated round robin style, a
   few each interrupt.  This should spread the load more evenly, and perhaps
   increase performance to an acceptable level.

   C_0.24 -- 5/4/92
   C_0.23 -- 5/4/92
   ----------------
   (0.23) Added Degas loading and some general cleanup, still GFA 0.21 logic
   (0.24) General pic loading routines.

   C_0.22 -- 5/2/92
   ----------------
   added color palette and title screen

   C_0.21 -- 3/15/92
   ----------------- 
   uses same logic as GFA 0.21, but has bitmaps for pills

   GFA Ver 0.61a    2/8/92
   -------------------
   Re-vamped sprite system, routines for virus animation added
   animation is too much of a drain on processor resources. 
   barely playable on a 16MHz machine.
 
   GFA Ver 0.60 -- 12/14/91
   --------------------
   Internal Cleanup in preparation for C translation
       (check_lines and erase_lines are MUCH nicer)
 
   GFA Ver 0.58 -- 11/20/91
   --------------------
   Fixed small bug that occasionally preventing game from ending
      when it should (Stooooooopid mistake!)   (thanx Mom!)
 
   GFA Ver 0.57 -- 7/31/91 -- RELEASED AS VER 0.85b (oops!)
   -------------------
   Joystick routines added(0.57)
   Sadistic music added as an experiment(0.56)
 
   GFA Ver 0.55 -- 6/23/91
   -------------------
   Levels now function. Game is playable as is
   Needs Title Screen, sound, animation and cleanup
 
   GFA Ver 0.52 -- 6/21/91
   -------------------
   Added routines to implement virus display and scoring
 
   GFA Ver 0.50 -- 6/21/91
   -------------------
   Lots of Changes -- Pills now have proper shape (tops, sides etc)
   Added all changes to checking routines to implement various shapes
   Pills that are linked now have bonds and hold each other up!
 
   GFA Ver 0.40 -- 6/19/91
   -------------------
   Replaced boxes with actual bitmaps
   Added Background Picture --------- Things are getting REAL cool!

   GFA Ver 0.31 -- 5/26/91
   -------------------
   Added routines to allow individual pill pieces to fall
 
   GFA Ver 0.30 -- 4/20/91
   -------------------
   Added boxes instead of debug numbers
   Began Coding routines to check/erase lines

   GFA Ver 0.21 -- 4/18/91
   -------------------
   First version as Dr. Necro
   Replaced screen point checking with an array lookup -- much faster
 
   GFA Ver 0.14 -- 1/20/91
   -------------------
   Originally the beginnings of a Tetris clone...
   The main logic for Dr. Necro was "extracted" from here.