Move classes from net.imglib2.img to net.imglib2.ij

[gab1one]

The packages net.imglib2.img net.imglib2.display.projector and net.imglib2.img.display are already contained in imglib2, therefore they should not be used here. By adding the common ij infix to the package names this is avoided for current and future packages.

[tpietzsch]

I think this is a good idea.

Because this breaks API completely, I think it would be a good opportunity to clean up and revise the package structure in general. For example some of the things in net.imglib2.img are actually Imgs
and could move to subpackage net.imglib2.ij.img instead of just net.imglib2.ij. Etc.

[axtimwalde]

Is there a new law in town that doesn't allow me to reuse package names across artifacts? I am all in favor of cleaning up and breaking historic stuff where necessary but not with this pull request which doesn't help anything but only satisfies a new arbitrary policy that I haven't subscribed to.

[tpietzsch]

Java 9 does not allow split packages in different modules.
So planning ahead to eventually modularizing the fiji world, this is a good idea...

[axtimwalde]

Ah! Thanks for the pointer. Then, this of course makes sense. Java 9 spinnt! But since nobody observed this policy before, shouldn't this be a more concerted effort across all of imglib2?

[tpietzsch]

Ideally, yes. But it can be done artifact by artifact.

Using artifact names as package prefixes seems to be a reasonable approach. So imglib2-ij goes to net.imglib2.ij. Other artifacts, e.g., imglib2-realtransform and imglib2-cache already follow this approach.

As a PR this is not very useful, I'm closing it and opened issue #25 instead.

[tpietzsch]

One question is what should happen to imglib2 (core) artifact.
Move everything under net.imglib2.core? Or just be careful not reuse any of the package names as artifact names?

[axtimwalde]

Weird---right? No opinion yet. Probably being careful would be good enough for starters and less disruptive.