FindAndReplace by Tommaso:

FindAndReplace by Tommaso:

- solves some issues related to the dialog set-up
 (overlapping of dialog title with upper sub-widget),
 by "borrowing" the widget structure from
 ViewSource.{h,cpp}
- reduces the default occupation of the dialog (in particular,
 it was "colliding" with the ViewSource itself);
- proposes to introduce a tabbed-panel in the F&R
 dialog, so as to have a "basic" and "advanced" tabs;
 (one option could be to make the dialog even smaller
  by moving all of the replace-related stuff into a separate
  "Replace" tab)

- recovers the eventFilter functionality back, so as to catch
 "Enter" or "Esc" key presses while in the Search Work Area

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@27967 a592a061-630c-0410-9148-cb99ea01b6c8