Let ij-app depend on ij-ops

For now, the ij-ops version is not listed in pom-scijava...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add the op() method to the ImageJ gateway

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Let Dataset extend the Img interface

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Implement almost all Img methods in DefaultDataset

This commit adds implementations of the Img methods that basically all
hand off to the wrapped ImgPlus.

The only method not implemented yet is the ImgFactory: we will most likely
want to wrap the ImgFactory returned by getImgPlus().factory() but
generate new Dataset instances, of course.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Merge branch 'ops'

This branch integrates imagej-ops into the ImageJ gateway so you can
call

	ImageJ imagej = new ImageJ();
	imagej.op().equation(...);

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