oiiotool --dumpdata and some "deep" fixes

Option to print all pixel values.  Not especially recommended unless you are debugging individual data values in a file.  

Works for deep files, too!  

Along the way, I fixed a little buglet in deep EXR writing -- it seems that only "zips" compression works well for deep EXR, so force it.

Fix another bug when writing tiled deep exr images: botched the IlmImf call when dealing with WriteTiles of a batch of tiles that don't start at the origin.