Updated all plugins that are non-forked. Added some new plugins.

Added update_plugins.py which can fetch new plugins from GitHub.

New plugins added: zencoding, vim-indent-object, taglist, nginx.vim

sources_non_forked/snipmate-snippets/javascript-jquery/ajaxgetif.snippet

@@ -0,0 +1,3 @@
+$.getIfModified('${1:/test/test.cgi}', function(data){
+	${2:alert( "Data loaded: " + data ) //optional stuff to do after get;}
+});