Move auto close empty group feature to own package

🎉 thanks to @LynnHo

It's over at github.com/math2001/AutoCloseEmptyGroup

Author: math2001

FileManager.py

@@ -64,30 +64,6 @@ def run(self, edit, **kwargs):
 
 
 class FmListener(sublime_plugin.EventListener):
-    def on_pre_close(self, view):
-        # a hack to detect tabless views, see comment below
-        # press alt+shift+2. Do you see the empty view on the right? That's
-        # what I call a tabless view.
-        # It doesn't have a tab, but ST still sees it as a view
-        if view not in view.window().views():
-            view.settings().set("auto_close_empty_group_is_tabless_view", True)
-
-    def on_close(self, view):
-        if get_settings().get("auto_close_empty_groups") is not True:
-            return
-
-        # A closed even is triggered for tabless views when an actual file
-        # is opened. Without this check, the pane that the edit_settings
-        # command created was automatically closed
-        if view.settings().get("auto_close_empty_group_is_tabless_view") is True:
-            return
-
-        window = get_window()
-        for group in range(window.num_groups()):
-            if len(window.views_in_group(group)) == 0:
-                window.run_command("close_pane")
-                return
-
     def on_load(self, view):
         settings = view.settings()
         snippet = settings.get("fm_insert_snippet_on_load", None)