add .editorconfig

Author: linkkingjay

.editorconfig

@@ -0,0 +1,13 @@
+# http://editorconfig.org
+root = true
+
+[*]
+end_of_line = lf
+charset = utf-8
+indent_style = space
+trim_trailing_whitespace = true
+insert_final_newline = true
+indent_size = 4
+
+[*.md]
+trim_trailing_whitespace = false