[FIX] search view layout in case of very long facet value

[FIX] search view layout in case of very long facet value

* don't fix facet height so the facet content correctly "grows" all of
  the facet and thus the surrounding view

* hard-code the heights of the view-level controls (clear and open
  drawer) to avoid both overly large hitbox and their moving outside
  of the top-right corner

* add some margins on the facets container to avoid overlaps between
  top-level search controls and facet activable elements

lp bug: https://launchpad.net/bugs/1123704 fixed

bzr revid: xmo@openerp.com-20130605105240-h9o03ol7l8dti1yn