BUGFIX for null-byte at nth-child selectors

[RichardCox09]

Consider the following example:

.foo:nth-child(2){
    margin-top: 2px;
}

The validator parses a null-byte before the number (2), because no operand is specified. This caused that the browsers couldn't understand the style.

[ylafon]

Please note that the output is not meant to be a preprocessor, that said, thanks for this, the \0 was indeed plain wrong.