Engage an "overlapped I/O" on Windows

[erthink]

Windows is the mad descending OS... However, some users still use it.

Related to kriszyp/lmdb-js#24 (comment)

[Llorx]

Hi, there are plans to fix this? I mean, just to know if there's any ETA or not.

[erthink]

Two major points related to this:

1. I wanna to have a strong stable baseline version before any consequent changes.
   The situation was close to such point but an unexpected problem appeared on the side of the linux kernel.
   So, hopefully, we will be able to continue development from May, if no bugs are found in April.
2. The development is mostly funded by Positive Technologies, so support for Linux and e2k is much more priority compared to Windows.
   This does not apply to bug fixes, but to a minor issues like performance improvement under Windows are.

[Llorx]

Oh, I see. Thank you for your input!

[erthink]

Done since 0.12.x