ImageJ 1.x'ify it

To make it recordable, we should use a GenericDialog.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add the Bio-Formats ImageJ plugin to the dependencies

Otherwise run('Bio-Formats') cannot work...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make image loading work when called via main()

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