Since we do not want to use the binary of nsProcess (https://nsis.sourceforge.io/NsProcess_plugin),
we compile the source code of the NSIS Plugin. Unfortunately it seems to be quite old. That's
why I (@ann0see) updated it on 2020-02-06 to support compilation
with Visual Studio 2019. Probably a lot more could be done to this.

According to Anders from the NSIS forum:

> The nsProcess plug-in also exists on the NSIS wiki and all files on this wiki are ZLib licensed unless otherwise noted.

See: http://forums.winamp.com/showthread.php?t=230998&page=2

And: http://forums.winamp.com/showpost.php?p=3200634&postcount=68
