Make the determination of the type of view currently displayed stronger.

This solves problems where, especially for a block editview, you would
suddenly lose the commit/delete buttons after changing a row.

This works as follows:
  * The URL the Javascript posts to now ends on the editview type
    (instead of ending on /editview_submit it now ends on
     editview_submit_editview_compressed or editview_submit_editview_table)
  * In hook_menu, both URLs map to the same function editview_render_node,
    but it gets an argument to determine the view type
  * editview_node gets a third optional argument, again with the view type
  * If the view is reloaded after a post, the type property is not set.
    We set it by hand from this additional argument.
  * The old code fragment which fudged the type property is removed, as
    this made some assumptions that did not work out