Enable wildcard MSL with multiple Launchers as with single Launcher

When setting up a single Launcher source directory there is no need to specify which MSL files to run. The single Launcher event will go to the assigned directory and find/run all MSL files found.

This is effectively a wild card usage of *.msl.

We have taken great advantage of this behavior in order to change which MSL files are launched, especially during testing. We can target a specific workflow by removing all other MSL files, or test variations on an existing workflow, without having to change the Launcher setup in any way.

But when running multiple Launchers as built using launcheradmin, the source targets are no longer directories but specific MSL files. While a directory is still selected, each MSL file must also be added to the set that will be launched.

This effectively eliminates the wild card *.msl feature and demands a list of specific MSL files when running a multiple Launcher session.

With multiple Launchers there is no capability to change the launched MSL files by simple adding or removing them from the directory.

It would greatly simplify the construction of environments using multiple Launchers if the user selected a directory for each system to be launched and gave the collection a processing name. Nothing more is required. As with the single directory selection, any MSL files found in the system source dirs are loaded at startup.