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/getjson.snippet

@@ -0,0 +1,5 @@
+$.getJSON('<+/path/to/file.cgi+>',{
+ <+<+param1+>: "<+value1+>", <+param2+>: "<+value2+>"+>},
+ function(json){
+    <+//stuff to do after event occurs;+>
+});