W32: Fix ReadKey with argument in the range 0 < x < 1.

[amba]

Fix bug #25.

Trying this change on a Windows7 VM fixes the problem for me.

The argument was changed from a double to U32 in commit 549f0e6:

-use DWORD everywhere, DWORD==U32, WaitForSingleObject takes integers not
FP numbers for the timeout

But with integers, you cannot properly scale from seconds to milliseconds.

[jonathanstowe]

Hmm,
I'll take your word for it that it works on Windows but it doesn't compile on Linux at all https://travis-ci.org/jonathanstowe/TermReadKey/jobs/220661941 - I'll need to take a look at it before I merge.

[amba]

Fixed.

[jonathanstowe]

Thanks. Not really got a schedule for the next release right now, but in the next month or so I'd guess :)

[amba]

This also fixes ReadKey(-1), which blocked forever with the U32 argument.

Would be great to have this in the next StrawberryPerl.
@kmx: What are your release plans?