Allow passing classloader to DefinitionGenerator

[GithubUser8080]

Currently DefinitionGenerator uses its own classloader to find classes. In the case of using this plugin at runtime (not scala task), in a play-dev application, the swagger generator is loaded by the dependency classloader that cannot find the user classes in app/mypackage ... etc

Since there is already a classloader argument, could this be passed to the definition generator too, to be used in runTimeMirror(myClassloader)? Thanks

[Javakky-pxv]

@GithubUser8080
We are currently reviewing it. It may take some time, but we plan to address it.