Interpreter.tryConvert should set cause exception

[remkop]

Interpreter.tryConvert should set cause exception, so that stack trace shows the cause (which may be a custom converter).

Should be:

        private Object tryConvert(ArgSpec argSpec, int index, ITypeConverter<?> converter, String value, Class<?> type)
                throws ParameterException {
            try {
                return converter.convert(value);
            } catch (TypeConversionException ex) {
                String msg = String.format("Invalid value for %s: %s", optionDescription("", argSpec, index), ex.getMessage());
                throw new ParameterException(CommandLine.this, msg, ex, argSpec, value);
            } catch (Exception other) {
                String desc = optionDescription("", argSpec, index);
                String msg = String.format("Invalid value for %s: cannot convert '%s' to %s (%s)", desc, value, type.getSimpleName(), other);
                throw new ParameterException(CommandLine.this, msg, other, argSpec, value);
            }
        }