Diffusion resources produce Jersey chatter

The Jersey server reports some warnings associated with Diffusion:

> 2018-02-07 16:41:46,053 [ResourcePublisher] WARN org.glassfish.jersey.internal.Errors - The following warnings have been detected: WARNING: Parameter 2 of type org.cytoscape.work.SynchronousTaskManager from public org.cytoscape.diffusion.internal.rest.DiffusionResource(org.cytoscape.application.CyApplicationManager,org.cytoscape.work.SynchronousTaskManager,org.cytoscape.model.CyNetworkManager,org.cytoscape.view.model.CyNetworkViewManager,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.ci.CIResponseFactory,org.cytoscape.ci.CIExceptionFactory,org.cytoscape.ci.CIErrorFactory) is not resolvable to a concrete type.
WARNING: Parameter 2 of type org.cytoscape.work.SynchronousTaskManager from public org.cytoscape.diffusion.internal.rest.DiffusionResource(org.cytoscape.application.CyApplicationManager,org.cytoscape.work.SynchronousTaskManager,org.cytoscape.model.CyNetworkManager,org.cytoscape.view.model.CyNetworkViewManager,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.ci.CIResponseFactory,org.cytoscape.ci.CIExceptionFactory,org.cytoscape.ci.CIErrorFactory) is not resolvable to a concrete type.
WARNING: Parameter 2 of type org.cytoscape.work.SynchronousTaskManager from public org.cytoscape.diffusion.internal.rest.DiffusionResource(org.cytoscape.application.CyApplicationManager,org.cytoscape.work.SynchronousTaskManager,org.cytoscape.model.CyNetworkManager,org.cytoscape.view.model.CyNetworkViewManager,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.ci.CIResponseFactory,org.cytoscape.ci.CIExceptionFactory,org.cytoscape.ci.CIErrorFactory) is not resolvable to a concrete type.
WARNING: Parameter 2 of type org.cytoscape.work.SynchronousTaskManager from public org.cytoscape.diffusion.internal.rest.DiffusionResource(org.cytoscape.application.CyApplicationManager,org.cytoscape.work.SynchronousTaskManager,org.cytoscape.model.CyNetworkManager,org.cytoscape.view.model.CyNetworkViewManager,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.diffusion.internal.task.DiffusionContextMenuTaskFactory,org.cytoscape.ci.CIResponseFactory,org.cytoscape.ci.CIExceptionFactory,org.cytoscape.ci.CIErrorFactory) is not resolvable to a concrete type.

A similar issue was present in CyREST, and was fixed by replacing ```?``` as the generic with ```Object```, so that:
```java
private SynchronousTaskManager taskManager;
```
becomes:
```java
private SynchronousTaskManager taskManager;
```

This may require some other minor refactoring to implement.