Unsigned packages on windows cause trust warnings

```
09:44 <@cmr> brson: may want to consider setting up https://www.certum.eu/certum/cert,offer_en_open_source_cs.xml to sign the windows installers, they get trust warnings 
             right now.
09:45 <@brson> awesome. i'll file a bug on it
09:45 <@cmr> it's especially obnoxious on windows 8/10 where you have to dig through a dialog to get it to actually run the exe

```
