* src/filetree.{cc,h} (FileTree::find_matches_at_path_iter):
Rename from find_matches_at_iter(): add a path parameter and
use it instead of obtaining the path from the iter argument.
(FileTree::replace_matches_at_path_iter): Rename from
replace_matches_at_iter(): add a path parameter and use it.
(FileTree::find_matches): Use TreeModel::foreach() rather than
foreach_iter() in order to gain a minor performance improvement
by taking advantage of the supplied Gtk::TreePath.
(FileTree::replace_all_matches): ditto.