LocalZProjector for large images opened as virtual stacks in Fiji.

We now are able to address large images that do not fit in RAM.

Fiji offers a simple solution for such a large images: open them as virtual stacks. In this case, each slice of the data is read from disk, on request. This PR ships a new version of the LZP plugin that exploit this, and generate and projection in two pass, exploiting the fact that we can process slice-by-slice.

It works but we needed to make sacrifices:

• you cannot project with median anymore.

Otherwise it works great.