Windows: Opening ports COM9+

[Tezar]

No directly problem of library, but could be at least hinted in docs.
When trying to open ports higher than COM9, you have to use special prefix e.g. ".\COM10"
This prefix is NOT included while enumeratig. According to the microsoft, you can always use the prefix even for lower ports, so this could be easily enforced in hx.

Will gladly make PR if it is deemed worthy.

ref:
https://support.microsoft.com/en-us/help/115831/howto-specify-serial-ports-larger-than-com9

[andyli]

Hi, thank for the tip. I haven't done anything with hxSerial for a long time and it's unlikely change soon. I'm happy to merge any useful-looking PRs though.