String trimming all parameter values returned by parameter::get. Was motivated to do this after I was contacted by Gregor Obernoster who couldn't get acs_community_member_link to work because of an accidental trailing slash in the CommunityMemberURL param.
Peter: adding the localize switch to parameter::get that will replace any #message_key# occurencies in the parameter value with the corresponding messages from the message catalog using the locale of the request