Add .editorconfig

.editorconfig

@@ -0,0 +1,14 @@
+root                     = true
+
+[*]
+end_of_line              = lf
+insert_final_newline     = true
+trim_trailing_whitespace = true
+charset                  = utf-8
+
+[{*.lua,*.tl,}]
+indent_style             = space
+indent_size              = 2
+
+[Makefile]
+indent_style             = tab