This is the end of ImgLib1 as we know it

Starting with this commit, ImgLib1 will be phased out.

To make phasing out easier, the SPIM Registration project at
https://github.com/fiji/fiji/tree/master/src-plugins/SPIM_Registration/
will add ImgLib2 wrappers for ImgLib1 data structures.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge remote-tracking branch 'github/end-of-imglib1'

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>