Directly produce .worker file

[gjbex]

In some settings, it would be useful if wsub and wresume could produce a .worker file directly, without forcing the user to use the -dryrun option, and fishing in the resulting hidden worker directory.

[gjbex]

witems, a derivative of wsub, has been added to produce a work items file from data sources. The same has to be done for wresume, creating wremains.