Description

Add (intuitive) support for pinning the output of a pipeline stage while other stages are edited.

Justification

Suggested in #569.

Instructions for Use

You can click the pin button on the right side of the results toolbar to pin the output of a pipeline stage so that it continues to be displayed while you edit other stages in the pipeline, letting you see how your changes impact things down the line.

Implementation Details

1. How did you test the change? Be descriptive. Untested code will not be accepted.
   Tested editing the pipeline for the Fiducial Camera when running with -DoverrideUserConfig=true. Tested navigating by both the pipeline panel and the navigation buttons, with and without stages pinned.
2. Did you follow the coding style?
   I believe so.
3. If you made changes in the org.openpnp.spi or org.openpnp.model packages you will need to add additional justification for these changes. Changes to these packages require extensive review and testing.
   No changes.
4. Be sure to run mvn test before submitting the Pull Request. If the tests do not pass the Pull Request will not be accepted.
   Done.