"'Default' tag requires a nonempty 'Extension' attribute" on Win10

I'm trying to build an installer, but when I try to run it the installation fails with `'Default' tag requires a nonempty 'Extension' attribute`:

```
2016-02-25 08:03:31> IEnableLogger: Failed to create uninstaller registry entry: System.Xml.XmlException: 'Default' tag requires a nonempty 'Extension' attribute. Line 10, position 4.
```

I've done some googling around and it appears to be an issue with files without extensions.

The `template.nuspec` tries to create a `LICENSE` file. Removing the relevant line from `` seems to resolve the problem.

If you think it's ok to not have that `LICENSE` file, I can easily submit a PR.