Add imglib-{scripting,ops,test} to legacy-imglib1

Stephan Preibisch pointed out that we should actually merge all of
ImgLib1 into legacy-imglib1 in order to send the message to all users
that this is now deprecated.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Avoid hardcoding versions in pom.xml

... when we can use versions defined in pom-scijava instead.

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