Add BeanShell as an optional dependency, for testing

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Show UI for legacy editor test drive

This is required to auto-generate a dialog for input parameters.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Handle @Parameters in the ImageJ 1.x macro engine

By nature, the support is limited to data types that ImageJ 1.x macros
can actually handle...

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