Midway MCR3scroll port for MiSTer

Original readme (mostly irrelevant to MiSTer)

Keyboard inputs :

   ESC         : Coin 1
   UP,DOWN,LEFT,RIGHT arrows : Player 1
   LCtrl  : Fire A
   LAlt   : Fire B
   Space  : Fire C   
   LShift : Fire D
   Z      : Fire E
   X      : Fire F 

   MAME/IPAC/JPAC Style Keyboard inputs:
     1           : Start 1 Player
     2           : Start 2 Player
     R,F,D,G     : Player 2
     A           : Fire2 A
     S           : Fire2 B 
     Q           : Fire2 C
     W           : Fire2 D
     I           : Fire2 E
     K           : Fire2 F
	
 Joystick support.

Games

Spyhunter

Supports digital and analog Steering, Gas.

Left/Right - Steering
A - Machine Guns
B - Smoke Screen
C - Weapons Van
D - Missiles
E - Oil Slick
F - Shift

Crater Raider

Up to 2 players. Supports 2 control modes: Joystick/Spinner

Joystick

Up/Down/Left/Right - movements
A - Fire
B - Shield
E - START2
F - START1

Spinner

Left/Right - Spinner
Up - Forward
Down - Reverse
A - Fire
B - Shield
E - START2
F - START1

Turbo Tag

Up to 2 players. Supports digital and analog Steering, Gas.

Left/Right - Steering
A - LButton/1Player
B - LTrigger
C - Center Button
D- RButton/2Player
E - RTrigger

ROMs

                                *** Attention ***

ROMs are not included. In order to use this arcade, you need to provide the
correct ROMs.

To simplify the process .mra files are provided in the releases folder, that
specifies the required ROMs with checksums. The ROMs .zip filename refers to the
corresponding file of the M.A.M.E. project.

Please refer to https://github.com/MiSTer-devel/Main_MiSTer/wiki/Arcade-Roms for
information on how to setup and use the environment.

Quickreference for folders and file placement:

/_Arcade/<game name>.mra
/_Arcade/cores/<game rbf>.rbf
/_Arcade/mame/<mame rom>.zip
/_Arcade/hbmame/<hbmame rom>.zip

Launch game using the appropriate .MRA