(langsys_tag): New variable.

(langsys_tag): New variable.
(get_features): Check if rec->langsys and rec->features are not
NULL.
(update_seq_area): Delete unused var.
(setup_feature_rec): Setup rec->langsys correctly.  Don't allocate
rec->features here.
(compose_script_langsys, decompose_script_langsys): New functions.
(ScriptProc): Fix handling of the arg call_data.
(create_otf_script_widgets): Check all langsys.  Allocate
gsub.features and gpos.features here.
(create_otf_widgets): Delete unused var.