Function encodeEscaped

This function:

1. Keeps regular spaces, only ' ', as they are.
2. Converts \n \r \t to escaped versions, \\n \\r and \\t.
3. Converts other control characters to their Unicode escape sequences.\
4. Converts ' " to escaped versions, \\\\' \\\\ and \\"

Unless you're using this in a JSON.stringify replacer, you probably want to use encodeEscapedWrapped instead.