Add to documentation that font needs to be installed on RPi

[cryptax]

On a Raspberry Pi, to use the python3 examples, you also need to install sudo apt-get install fonts-wqy-microhei or you will get an error:

Drawing
traceback.format_exc():
%s Traceback (most recent call last):
  File "main.py", line 22, in <module>
    font24 = ImageFont.truetype('/usr/share/fonts/truetype/wqy/wqy-microhei.ttc', 24)
  File "/usr/local/lib/python3.5/dist-packages/PIL/ImageFont.py", line 280, in truetype
    return FreeTypeFont(font, size, index, encoding, layout_engine)
  File "/usr/local/lib/python3.5/dist-packages/PIL/ImageFont.py", line 145, in __init__
    layout_engine=layout_engine)
OSError: cannot open resource

This should be added to the documentation.

[waveshare]

yes,thinks ,i will fix readme

[k4m454k]

i found a font here.
https://github.com/byrongibson/fonts/tree/master/truetype/wqy

[waveshare]

try:
sudo apt-get install ttf-wqy-zenhei ttf-wqy-microhei

[waveshare]

Now you can see it in the readme.txt