small change to VFindMode.activate
small change to VFindMode.activate

* child.wnd.focus won't cause tab switching
* inject <count> in wnd.onload
  * it seems that the first paint is very early
  * so a timeout is not so useful
* VFindMode should be active immediately after @activate,
  because it has no other status info
* move code for shorter style recalcing (not less, though)
* remove a setTimeout for less painting

gdh1995/vimium-plus,gdh1995/vimium-plus,gdh1995/vimium-plus