Fixed issue/idea 30th from eMBee list - added command (and keyboard shortcut), which removes all tags from message

lib/sup/modes/thread_index_mode.rb

@@ -41,6 +41,7 @@ class ThreadIndexMode < LineCursorMode
     k.add :toggle_new, "Toggle new/read status of all messages in thread", 'N'
     k.add :edit_labels, "Edit or add labels for a thread", 'l'
     k.add :edit_message, "Edit message (drafts only)", 'e'
+    k.add :pure_labels, "Remove all labels from message", 'Z'
     k.add :toggle_spam, "Mark/unmark thread as spam", 'S'
     k.add :toggle_deleted, "Delete/undelete thread", 'd'
     k.add :kill, "Kill thread (never to be seen in inbox again)", '&'
@@ -606,6 +607,54 @@ def edit_labels
     Index.save_thread thread
   end
 
+  def pure_labels
+    thread = cursor_thread or return
+    speciall = (@hidden_labels + LabelManager::RESERVED_LABELS).uniq
+
+    old_labels = thread.labels
+    pos = curpos
+
+    keepl, modifyl = thread.labels.partition { |t| speciall.member? t }
+    thread.labels = Set.new(keepl)
+
+    update_text_for_line curpos
+
+    UndoManager.register "labeling thread" do
+      thread.labels = old_labels
+      update_text_for_line pos
+      UpdateManager.relay self, :labeled, thread.first
+      Index.save_thread thread
+    end
+
+    UpdateManager.relay self, :labeled, thread.first
+    Index.save_thread thread
+  end
+
+  def multi_pure_labels threads
+
+   speciall = (@hidden_labels + LabelManager::RESERVED_LABELS).uniq
+   threads.each do |thread|
+    old_labels = thread.labels
+    pos = curpos
+
+    keepl, modifyl = thread.labels.partition { |t| speciall.member? t }
+    thread.labels = Set.new(keepl)
+
+    update_text_for_line curpos
+
+    UndoManager.register "labeling thread" do
+      thread.labels = old_labels
+      update_text_for_line pos
+      UpdateManager.relay self, :labeled, thread.first
+      Index.save_thread thread
+    end
+
+    UpdateManager.relay self, :labeled, thread.first
+    Index.save_thread thread
+   end
+  end
+
+
   def multi_edit_labels threads
     user_labels = BufferManager.ask_for_labels :labels, "Add/remove labels (use -label to remove): ", [], @hidden_labels
     return unless user_labels