Adapt HTMLRenderer NavigationView init args to new signature

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21560 4ae1f11a-8b86-4847-b8af-ab372f36d1fd
get_unicode_path_from_env_var(): make no-op if it's already unicode

git-svn-id: svn+ssh://svn.code.sf.net/p/gramps/code/trunk@21561 4ae1f11a-8b86-4847-b8af-ab372f36d1fd