remove deprecated methods and sginals

[Curtis Hovey]

Deprecated code that is changeable for natty and maybe lucid.
    * WebKitWebView::load-finished is deprecated and should not be used
      in newly-written code.
      Use the "load-status" property instead.
    * webkit_web_view_open has been deprecated since version 1.1.1 and
      should not be used in newly-written code.
      Use webkit_web_view_load_uri() instead.
    * webkit_web_view_load_html_string has been deprecated since version 1.1.1
      and should not be used in newly-written code.
      Use webkit_web_view_load_string() instead.
    * WebKitWebView::title-changed has been deprecated since version 1.1.4
      and should not be used in newly-written code. Use "notify::title"
      instead.