[kepler-dev] Combined commandline and exec actors

[Ilkay Altintas]

Dear All,

I've just checked in the changes for Bilsay's combined version of the 
old CommandLine and Exec actors that Christopher and I have 
concurrently implemented last year.

The new actor is named "CommandLineExec" to have a different name and 
avoid conflicts.

The old actors are kept so that none of the existing workflows that use 
them will crash. It would be great if you could check your existing 
workflows at your convenience to adopt the new actor.

We would like to adopt the new actor in the future workflows so the old 
actors don't show up in the actor library.

Hope this change is not going to cause any inconvenience for anybody. 
We appreciate if you can test it and send comments before Bilsay's 
internship ends in a few weeks.

Bilsay: I think we need to have an error port in the new interface to 
divert the standard error messages to. It is not an output but quite 
important for usability of the actor.

Thanks very much to all!
-ilkay