bin/ImageJ.sh: support --classpath=<path>

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
bin/ImageJ.sh: support versioned .jar files

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
bin/ImageJ.sh: support --java{c,h,p,doc}

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