Remove restriction for monitor mode on Windows

[LauJosefsen]

I suggest removing the arbitrary restriction for not allowing monitor mode on win32.

It seems the original pull request adding the restriction argued that it was necessary due to winpcap not supporting monitor mode, but npcap does. I have tried removing the restriction locally, and was able to sniff Wi-Fi frames in monitor mode on Win32 using npcap without any obvious issues.

Added with PR #174, can be solved by merging PR #531