Replace exo- functions with xfce-string

configure.ac.in

plugins/thunar-sendto-email/Makefile.am

plugins/thunar-sendto-email/main.c

plugins/thunar-uca/thunar-uca-model.c

thunar/Makefile.am

thunar/thunar-browser.c

thunar/thunar-clipboard-manager.c

thunar/thunar-column-model.c

thunar/thunar-dbus-service.c

thunar/thunar-device-monitor.c

thunar/thunar-dnd.c

thunar/thunar-emblem-chooser.c

thunar/thunar-enum-types.c

thunar/thunar-file-monitor.c

thunar/thunar-file.c

thunar/thunar-folder.c

thunar/thunar-gio-extensions.c

thunar/thunar-history.c

thunar/thunar-icon-factory.c

thunar/thunar-job.c