Sign zen player executable

[jwalthour]

[jwalthour]

Ugh, merely signing isn't enough. In eba32fa I added basic signing, but it had no effect.

It looks like what I need to do involves "ClickOnce", and it's easy to find the options for that in visual studio: https://docs.microsoft.com/en-us/visualstudio/deployment/trusted-application-deployment-overview?view=vs-2015 But it looks like that might still require end users to manually trust the certificate, which seems undesirable.