Not usable on Windows due to `fcntl`

[paw-lu]

This is mostly an FYI due to #18 and #17 being open.

The fcntl module is apparently unsuported on Windows. Attempting to run raises:

ModuleNotFoundError: No module named 'fcntl'

Didn't know this myself until some Windows tests were failing..

[jsbueno]

fcntl is unix only -
as yopu noted, it is great to have this here as a marker.

For some of the features, tough, the project should work as is on windows: fcntl should be a guarded import and the lib should, though unable to handle keyboard or mouse, work on windows.

If "import terminedia" is failing on Windows, this has a higher priority to be fixed than try to get everything working smoothly.

[paw-lu]

If "import terminedia" is failing on Windows

I don't have a windows machine, but if according to the traceback this seems to be exaclty what is happening.