Fix redrawing prompts on Windows

[mislav]

Fixes redrawing prompts on Windows so that:

1. The line before the 1st survey prompt isn't accidentally deleted,
2. The survey prompt is properly redrawn after recording an answer.

For help with debugging Survey, this also adds logging support by setting SURVEY_LOG_FILE environment variable.

Fixes #368
Closes #458

TODO:

• test in more different terminal combos
• test cursor handling when a prompt or an answer wraps due to viewport width

[andyfeller]

@mislav : thank you for working towards the root of this issue for Windows users ✨

What might you share about this work for someone else to pick it up and carry it to completion?