Make explicit calls ascii versions of Windows functions

Windows API allows you to choose whether to call the ASCII, or Unicode versions of their APIs. You can either call the API with A or W if you want to be explicit or let preprocessor defines dictate which version is chosen.

Currently, WT is uses the naked API calls like CreateFile which can either become CreateFileA or CreateFileW depending on preprocessor defines. With change, I have chosen to explicitly call the ascii versions to be clear.