Make dividers unicode

Fixes travis problem with old vim

powerline/theme.py

@@ -32,6 +32,11 @@ class Theme(object):
 				run_once=False,
 				shutdown_event=None):
 		self.dividers = theme_config.get('dividers', common_config['dividers'])
+		self.dividers = dict((
+			(key, dict((k, u(v))
+			for k, v in val.items()))
+			for key, val in self.dividers.items()
+		))
 		self.spaces = theme_config.get('spaces', common_config['spaces'])
 		self.segments = []
 		self.EMPTY_SEGMENT = {