Sort out meta namespace in widgets

[mikeyg]

Currently the meta NS is being specified in the root (vexi) element. Like so...

<vexi xmlns:meta="vexi://meta" xmlns="..." >
   <meta:doc>
      <author
  </meta:doc>
  ...

Here either we should prefix all the meta:doc sub elements with meta to have the correct namespace. A better way of doing it would probably be (need to verify that this works as intended) overriding the default namepsace

<vexi xmlns="..." >
   <doc xmlns="vexi://meta">
      <author
  </doc>
  ...