add .editorconfig

.editorconfig

@@ -0,0 +1,17 @@
+root = true
+
+[*]
+end_of_line = lf
+insert_final_newline = true
+
+[*.js]
+charset = utf-8
+indent_style = space
+indent_size = 2
+
+[Makefile]
+indent_style = tab
+
+[{package.json,.travis.yml}]
+indent_style = space
+indent_size = 2