[less] add less test block to test.html
[less] improve test-less.html's thoroughness
[less] improve test styling
[less] improve css.FUNCTION, css.AT_RULE
[less] replace css.selector things with css.SELECTOR mode
[less] add css.VALUE and css.PROPERTY modes
[less] implement css.HEX_COLOR and css.COLOR_KEYWORD more fully
[less] fix relevance; also cleanup, reorder