topic-branches.sh: let the environment variable REMOTE override

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
download-launchers.sh: we can use --set-icon for the Windows icon now

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
download-launchers.sh: copy ./fiji from ./fiji-<platform>

... instead from ./ImageJ-<platform> (to help correct keep icons).

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
download-launchers.sh: no longer fix ij-launcher.jar

The idea is that even ij-launcher.jar should be handled by
Retrotranslator; besides, we do not ship ij-launcher.jar from the
Fiji update site and the ImageJ update site (which does ship said
.jar file) does not fix the classes anyway.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
fiji-compat: avoid instantiating a Menu in headless mode

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Fix a couple of compiler warnings in fiji-compat's IJ1 hacking code

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Make sure that ImageJ2's legacy layer gets initialized

... before we start up ImageJ 1.x. This is needed for the upcoming
Help>Switch To Modern Mode.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
IJHacker: be nice if ij-legacy already defined some classes

We try to reconcile the Javassist-based IJ1 patching between ImageJ2
and Fiji, but for the time being, let ImageJ2 do its thing after
Fiji. That means that we only should make sure that the patched classes
are defined after ImageJ2 did its patching (and may have defined said
classes including Fiji's patches). So be prepared...

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add ij-app as a dependency of fiji-compat

This is needed for the upcoming Help>Switch to Modern Mode command.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Add Help>Switch To Modern Mode

Based on the recent improvements in ij-legacy.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Remove some unused imports

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