Float re

Add support for floating point image
To test this PR
 * make sure that the unit tests under ```server/test/omeis.providers.re.utests``` are green
 * Import floating point images. a selection can be found under ```squig/team/will/float0-data.zip```
 * View the image in OMERO, modify some values e.g. pixels window.
 * View the same image in ImageJ. 

Note that the pyramid generation for floating point images (>4kx4k)will not work. This will not be addressed in this PR.