Short term:

- add pod docs to ModuleLoad

- add pod docs about resources_required

- module load
    - option to get modules from $ENV{LOADEDMODULES}
      - instead of user-provided list

- add stage param extra_submit_args
  - make -extra_sge_args_string a synonym

Medium term:

- write a porting guide for driver writers

- design interface for file transport
  - send input files, return output files
  - needed for cluster

- write a 'driver' to display ordering from stage pre_req/dep info