Get OS-specific commands and args to correctly call peerflix for streami...

Get OS-specific commands and args to correctly call peerflix for streaming videos on Windows machines.

I added a variable to check if it's a Windows environment.  If it is, it uses 'cmd' as the command and passes '/c', 'peerflix' as arguments before passing the decoded URI and the port.  Otherwise, it reverts to the original code, calling 'peerflix' as the command and passing the decoded URI and port as arguments.

I have not tested this in Linux because I don't have a Linux machine set up with nodejs installed.