Add editorconfig

So editors can warn about line length etc

.editorconfig

@@ -0,0 +1,15 @@
+# EditorConfig: http://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+end_of_line = lf
+indent_size = 4
+indent_style = space
+quote_type = double
+insert_final_newline = true
+trim_trailing_whitespace = true
+max_line_length = 88
+
+[*.json]
+insert_final_newline = false