Faster git parsing

- fix a bug when removing nodes from huge dir
- only one `system` call for git status
- add relative paths to nodes
- parse git status from relative paths

lua/lib/format.lua

@@ -84,6 +84,7 @@ end
 local HIGHLIGHT_GROUPS = {
     ['^.*%.md$'] = 'MarkdownFile';
     ['^LICENSE$'] = 'LicenseFile';
+    ['^%.?vimrc$'] = 'VimFile';
     ['^.*%.vim$'] = 'VimFile';
     ['^.*%.c$'] = 'CFile';
     ['^.*%.cpp$'] = 'CFile';