Please document how to use unicode2gfx.py

[martinberlin]

Hi there @m5stack

There is a very short reference to unicode2gfx.py and actually no example of how can you can you call it from command line and get it to work.
I can of course open it and guess it myself but that is not the point. It will be nice that is documented in the Readme.

Also for me the GUI version in Linux is not working (Using Python3)

After selecting the font and size (Which is a bit weird how is done, because the size on the Input GUI is not used, then why it's there?)
I get this message:

Start Thread Thread-1
[xcb] Unknown sequence number while processing reply
[xcb] Most likely this is a multi-threaded client and XInitThreads has not been called
[xcb] Aborting, sorry about that.
python: ../../src/xcb_io.c:641: _XReply: Assertion `!xcb_xlib_threads_sequence_lost' failed.
Aborted (core dumped)

Also the from 0x00000 to 0x00000 is impossible to change. How you define a range?
It looks like a nice tool and it will be great that there is a better effort documenting it so more people can use it.