Workflow jobs

Added and implemented workflow jobs CREATE_CASE and LOAD_RESULTS. Added rerun argument to RUN_SMOOTHER job, and added realizations argument(s) to ENSEMBLE_RUN job. 

For LOAD_RESULTS, a new method enkf_main_load_from_forward_model() is added, and enkf_tui_run.c is changed to use this method.

The following "convenience/utility" methods are added: ert_workflow_list_has_job(), alloc_iactive_list_from_stringlist(), stringlist_iget_as_bool().