Protobuf compiler is downloaded to the .spine under an included project #552
Description
Currently it is not possible to create composite builds of Spine-based projects because of the following problem.
When a Spine-based project is added to a composite-build project via includeBuild(), and the project is evaluated during the composite build, we download the Protobuf Compiler plugin into the .spine directory, which is created under the included project. But when the plugin is used, we try to find it in the root project.
The workaround for this problem is to manually copy the .spine directory to the root of the composite build project.