fiji-compat: setting the context class loader moved to ij-legacy

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
IJ1Patcher: legacy headless support moved to ImageJ2

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
IJHacker: code to set the application name moved to ImageJ2

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Organize imports in FijiClassLoader

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
fiji-compat: move NoSuchMethodError handling to ij-legacy

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