look for tile locations under another key in .czi metadata

[hoerldavid]

This is a fix for missing Tile locations we encountered in a (corrupted?) CZI file (that prevented automatic loading of the whole dataset).
I found the tile location under an alternative key in the metadata, but I'm not familiar enough with CZI to assess whether looking under Experiment|AcquisitionBlock|TilesSetup|PositionGroup|Position| ... is a good idea or might cause problems with other datasets.

What are your thoughts @StephanPreibisch ? Should we merge this?

[hoerldavid]

Here's how I interpret the values:

• Information|Image|V|View|Position[X,Y,Z]|... is the actual location at which the image was taken
• Experiment|AcquisitionBlock|TilesSetup|PositionGroup|Position| ... is where we specified the image to be taken before running the acquisition.

Normally, those should be the same. Since we only fall back to the second value if we cannot find the first (which should not happen normally) this should not change behaviour for normal datasets, but might enable us to open "slightly corrupted" data, e.g. when the acquisition was interrupted halfway through.

I think this is save to merge, so let's do that before the next release @StephanPreibisch ?