Added localization for Wheelchair option

Languages:
Slovene, German, French, Italian and Catalan.

German, French, Italian and Catalan are added based on old Javascript
Localizations.

Conflicts:
	src/client/i18n/ca_ES.po
	src/client/i18n/de.po
	src/client/i18n/en.po
	src/client/i18n/fr.po
	src/client/i18n/it.po
	src/client/i18n/messages.pot
	src/client/i18n/sl.po