Remove 'before' key from file_vcs_status segment

Fixes #219

powerline/config_files/themes/vim/default.json

@@ -33,6 +33,7 @@
 			},
 			{
 				"name": "file_vcs_status",
+				"before": " ",
 				"draw_divider": false
 			},
 			{

powerline/segments/vim.py

@@ -282,7 +282,6 @@ def file_vcs_status(segment_info):
 					'contents': status,
 					'highlight_group': ['file_vcs_status_' + status, 'file_vcs_status'],
 					})
-			ret[0]['before'] = ' '
 			return ret
 	return None
 

powerline/theme.py

@@ -63,8 +63,17 @@ class Theme(object):
 					if contents is None:
 						continue
 					if isinstance(contents, list):
+						segment_base = copy(segment)
+						if contents:
+							for key in ('before', 'after'):
+								try:
+									contents[0][key] = segment_base.pop(key)
+									segment_base[key] = ''
+								except KeyError:
+									pass
+
 						for subsegment in contents:
-							segment_copy = copy(segment)
+							segment_copy = copy(segment_base)
 							segment_copy.update(subsegment)
 							parsed_segments.append(segment_copy)
 					else: