Add editorconfig to enforce whitespace rules

Author: raoulmillais

.editorconfig

@@ -0,0 +1,9 @@
+# top-most EditorConfig file
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+indent_style = space
+indent_size = 2
+charset = utf-8