Refactor display options

[NicoKiaru]

@tischi,

Here's the big refactoring. It removes a lot of stuff with bdv playground, but together with https://github.com/NicoKiaru/bigdataviewer-spimdata-extras and https://github.com/NicoKiaru/bigdataviewer_playground_display we get a better separation of tasks, the same functionalities as before, and an easier and more flexible to extend them.

This will require a bit of time to adapt your code, but it'll be worth.

We should be able to solve, or provide an easier way to fix:

• Blending of sources / custom converter #199 -> done in bigdataviewer_playground_display
• ProjectionMode #196 -> done in bigdataviewer_playground_display with more flexibility
• edit mode and group mode kill each other #140
• Average projection mode with sources across and within BDVDatasets #136
• Contrast inversion #131
• average projector, linear interpolationartefacts at bounding box #117
• Projection Layers #95
• Projection String Comparison #94

The two things which are allowing this is the serialization of the suppliers of Bdv, which allows to store preferences conveniently for how the bdv is build. I also added plugins which can basically handle any sourceandconverter operation based on a tag of xml of spimdata objects, when spimdata objects are loaded or saved ( think displaysettings, projection, and also custom converters for label images)

Maybe we should tackle #180 while we're at it.

[NicoKiaru]

Ok @tischi , let's go for it!

[NicoKiaru]

Hmm I'll fix #180 before