OpService: simplify how ops are run
OpService: simplify how ops are run

Now we *always* populate the module manually rather than relying on a
ModuleService#run method to do it for us. That way, we can avoid using
that method and instead just call Module#run() directly. This avoids:

A) spawning a new thread, which we then immediately wait to join; and
B) publishing a bunch of module execution events to the event service.

It may be necessary to move back to the ModuleService#run approach later
if we want pre- and post-processing, or we want event publication, but
for now it is simpler to just call run() directly for ops.

gab1one/imagej-ops,kephale/imagej-ops,imagej/imagej-ops,stelfrich/imagej-ops