Updated GEN_DATA initialisation to hard require that result file format contains %d
Removed debug message from gen_data load
Pure white-space change
Changed loading of results from forward model:

 - Created new function enkf_state_internalize_GEN_DATA() which loads
   GEN_DATA instances, irrespective of whether the variable type is
   DYNAMIC_STATE or DYNAMIC_RESULT.

 - The state_load function will only load FIELD instances from the
   ECLIPSE restart file.

 - The result_load function will only load eclipse SUMMARY variables.

 - It is a hard assumption that the summary nodes use vector storage
By setting the environment variable ERT_SHOW_BACKTRACE you will get the backtrace on stderr instead of a file.
Function enkf_state_load_ecl_sum() will check ecl_config_active() before loading.
If we ask for the last restart and do not have any history object - return 0 (with a warning on stderr).