Update to use fourwire and root_group for CP 9 compatibility

Author: prcutler

README.rst

@@ -44,20 +44,21 @@ Usage Example
 
     import board
     import displayio
+    import fourwire
     from adafruit_st7735 import ST7735
 
     spi = board.SPI()
     tft_cs = board.D5
     tft_dc = board.D6
 
     displayio.release_displays()
-    display_bus = displayio.FourWire(spi, command=tft_dc, chip_select=tft_cs, reset=board.D9)
+    display_bus = fourwire.FourWire(spi, command=tft_dc, chip_select=tft_cs, reset=board.D9)
 
     display = ST7735(display_bus, width=128, height=128)
 
     # Make the display context
     splash = displayio.Group()
-    display.show(splash)
+    display.root_group = splash
 
     color_bitmap = displayio.Bitmap(128, 128, 1)
     color_palette = displayio.Palette(1)

examples/st7735_simpletest.py

@@ -8,6 +8,7 @@
 
 import board
 import displayio
+import fourwire
 from adafruit_st7735 import ST7735
 
 # Release any resources currently in use for the displays
@@ -17,15 +18,15 @@
 tft_cs = board.D5
 tft_dc = board.D6
 
-display_bus = displayio.FourWire(
+display_bus = fourwire.FourWire(
     spi, command=tft_dc, chip_select=tft_cs, reset=board.D9
 )
 
 display = ST7735(display_bus, width=128, height=128)
 
 # Make the display context
 splash = displayio.Group()
-display.show(splash)
+display.root_group = splash
 
 color_bitmap = displayio.Bitmap(128, 128, 1)
 color_palette = displayio.Palette(1)