fix AttributeError: module 'collections' has no attribute 'Iterable'

collections.Iterable is deprecated. Replace it with
collections.abc.Iterable.

Author: Jean-Baptiste Poittevin

ftplugin/orgmode/liborgmode/base.py

@@ -13,7 +13,7 @@
 except:
 	from UserList import UserList
 
-import collections
+import collections.abc
 import sys
 from orgmode.py3compat.unicode_compatibility import *
 
@@ -31,7 +31,7 @@ def flatten_list(lst):
 	def gen_lst(item):
 		if isinstance(item, basestring) or isinstance(item, bytes):
 			yield item
-		elif isinstance(item, collections.Iterable):
+		elif isinstance(item, collections.abc.Iterable):
 			# yield from would be so nice... but c'est la vie
 			for val in item:
 				for final in gen_lst(val):