Update minitft_featherwing.py

[hexthat]

Set the SPI speed, I was having some issues with it being way to slow.

[jerryneedell]

@hexthat I don't know if you see the errors from the travis pylint but it wants you to fix the spacing on some continuation lines

************* Module adafruit_featherwing.minitft_featherwing
C: 84, 0: Wrong continued indentation (add 1 space).
                                        command=board.D6,
                                        ^| (bad-continuation)
C: 85, 0: Wrong continued indentation (add 1 space).
                                        chip_select=board.D5)
                                        ^| (bad-continuation)
C: 87, 0: Wrong continued indentation (remove 8 spaces).
                                       rotation=270, bgr=True)
                               |       ^ (bad-continuation)

[hexthat]

okay i fixed that line to what it was

[makermelissa]

Tested and it works great. Fixes #40 as well.