Update GraphViz plugin for Gephi 10

[dgehriger]

New plugin or plugin update?

• New Plugin
• Update

What is the purpose of this plugin?

It's just the original GraphViz plugin, but recompiled for the latest versions of Gephi and GraphViz. The original plugin would not longer work and perform any layout, due to its inability to read the dot output.

How to test your plugin in Gephi?

1. Install in Gephi
2. Use Graphviz Layouter

Checklist before submission

• Did you merged with the master branch to get the latest updates?
• Did you build and test the plugin successfully locally?
• Did you include metadata (e.g. plugin author, license) in the pom.xml file
• Did you make sure NOT to include any unecessary files in your PR?
• Did you write unit tests to test your plugin functionalities?

[dan-van]

Hi there, I also fixed this without thinking to check if someone else had issued a pull request without there being an open ticket.
In my version I added a bit of test coverage and handled some other cases that I thought might come up in different gephi usecases.

It would obviously be rather impolite for me to raise a second parallel pull request, but perhaps @dgehriger would want to take any useful bits I've done and integrate into this pull request?

I'm also pretty unclear on the correct approach to branching and requesting patches for plugins for which I am not the owner, sorry if I've based my commit on the wrong branch.

dan-van@e990347