disable autocomplete on filter input

git-svn-id: https://plugins.svn.wordpress.org/taxonomy-filter/trunk@1042918 b8457f37-d9ea-0310-8a92-e5e31aec5664
increased plugin's compatibility to older WordPress versions

git-svn-id: https://plugins.svn.wordpress.org/taxonomy-filter/trunk@1042954 b8457f37-d9ea-0310-8a92-e5e31aec5664