ZOMG UPDATES!

- Move all global vars into table g

- Remove notify_none from message tags

- Support fetching information about URL by pressing `i`.
  This is disabled by default. You have to set
  `plugins.desc.lua.urlselect.enable_info` to `yes` to enable it.
  This feature requires lua-cjson and socket.url (from lua-socket)
  modules.

  Currently it doesn't handle content-type correctly. It'll try to fetch anything
  (including big ass video file) and will fail hard. There's also no way
  to cancel the fetch process, so be careful when pressing `i`.