improve CSS tokenizer to exclude comments
updated README about #1e8bfa343de2ca63594bfb4c5792e85b047c3b2a
fix missing ; (semicolon) in the end of 'none;' due to some minifiers removing the last ; in a declaration block
fixed bug where charset rules would be tokenized - these rules can not have white-space:none declaration so we simply ignore them
updated readme with the 2 latest commits
fixed spelling error