Unix support

[TimJSwan89]

I am attempting to run the text editor on a mac. Is there a library that can be used? If not, can you add a README to say that the project depends on windows?

$ pip3 install win32
ERROR: Could not find a version that satisfies the requirement win32 (from versions: none)
ERROR: No matching distribution found for win32
$ pip3 install win32print
ERROR: Could not find a version that satisfies the requirement win32print (from versions: none)
ERROR: No matching distribution found for win32print

$ python3 textpad.py 
Traceback (most recent call last):
  File "textpad.py", line 6, in <module>
    import win32print
ModuleNotFoundError: No module named 'win32print'