Fixes bug related to remind button

The remind button was appearing even though "days before reminding" was
set to 0 if the review button title was set.

Source/Armchair.swift

@@ -1134,7 +1134,7 @@ public class Manager : ArmchairManager {
     }
 
     private func showsRemindButton() -> Bool {
-        return (remindButtonTitle != nil)
+        return (daysBeforeReminding > 0 && remindButtonTitle != nil)
     }
 
     private func showRatingAlert() {