Hi,
The license is necessary in order to build the .licenses resource from the .LICX in the project. The developer needs to build that on a machine with Spread installed and the license activated.
You can modify the project to include that .licenses file as an embedded resource, and then exclude the .LICX, and then the project can be built on a machine without the license installed (like your build machine). If you use source control, you can check in the project that way.
Hope that helps!
Regards,
-Sean