spell-check changes: add-new-word function now puts terms in temp file for assessment by admin before importing into site-specific personal dictionary; rebuilt en-medical.rws (extra-dict) from edited contents of old personal dict (.aspell.en.pws) - moved all acronyms/abbreviations into new personal dict (.aspell.leeds.pws); LIMS::_create_user_profile() adds users 'centre' param to session user_profile; adapted spellchecker.pl to work with new dictionary format
