- Fix the handling of actual occurrences of U+FFFD. - Fix an existing bug of QuoteVariableName("$\n").
In addition to fixing the encoding bugs standardize on \xNN notation for bytes rather than \uNNNN; e.g., \x00 rather than \u0000. Also, update the documentation for double-quoted strings to include the \e sequence. Fixes #1528
Also fix the error message of SetReadOnlyVar.