Environment language setting must match language of used esm/esp files

If the environment's language settings don't match the language of the used esm/esp files, upper/lower-case handling of names does not work properly. This can lead the malfunctions in the scripting system.

(RM-4 from redmine: created on 2011-08-06 by Lukasz Gromanowski, , closed on 2013-03-14 by nobody)