Documentation update.

Updated docs to point to --host cmdline option instead of deprecated --remote
option.
Untie recipe_id from rundir_id.

For some reason recipe_id was tied to rundir_id so that starting recipe id
depended on chosen run_dir. This tie is now removed.
RecipeData init while copying xml template.

Since RecipeData is now needed earlier (in copy_job_as_template() instead of
parse_job()) we'll need to check if it is properly initialized in that function
as well.