`relative' parameter to activate_uri

[Maciej Stachowiak <mjs eazel com>]

I suggest that the "relative" parameter to
Bonobo::ControlFrame::activate_uri be removed. It kind of begs the
question of "relative to what?". 

There does not seem to be a clear way to for the Control and
ControlFrame to agree on some base URI relative to which relative URIs
will be resolved, and there's no guarantee the container even has any
idea of a base URI; it might have never loaded the component from a
URI.

If the Control and ControlFrame _do_ have some back channel to agree
on a base URI (perhaps through another interface), the Control could
always do the resolution of the relative URI reference itself.

 - Maciej Stachowiak