remove unread first sorting: has issues, is pretty much adaptive anyway

include/functions2.php

@@ -665,10 +665,6 @@
 
 			$order_by = "score DESC, date_entered DESC, updated DESC";
 
-			if ($view_mode == "unread_first") {
-				$order_by = "unread DESC, $order_by";
-			}
-
 			if ($override_order) {
 				$order_by = $override_order;
 			}

index.php

@@ -176,7 +176,6 @@
 			<option value="marked"><?php echo __('Starred') ?></option>
 			<option value="published"><?php echo __('Published') ?></option>
 			<option value="unread"><?php echo __('Unread') ?></option>
-			<option value="unread_first"><?php echo __('Unread First') ?></option>
 			<option value="has_note"><?php echo __('With Note') ?></option>
 			<!-- <option value="noscores"><?php echo __('Ignore Scoring') ?></option> -->
 		</select>