Update less.js

Better handling of less code.
Fixed some issues.

Fix some issues add features.

Allow for indentation with ``(``
````
.outer2:hover {
  background-color: #050590;
  color: #F0F0F0;
  //border-color: #759dc0;
  //background-image: linear-gradient(left, rgba(0, 0, 0, 0.7) 0%, rgba(0, 0, 0, 0) 100%);
  background-image: linear-gradient(right , rgba(0,0,0, 0.7) 0%, rgba(0,0,0,0) 100%);
  background-image: -o-linear-gradient(right , rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 100%);
  background-image: -moz-linear-gradient(right , rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 100%);
  background-image: -webkit-linear-gradient(right , rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 100%);
  background-image: -ms-linear-gradient(right , rgba(0,0,0,0.7) 0%, rgba(0,0,0,0) 100%);
  
  background-image: -webkit-gradient(
    linear,
    right top,
    left top,
    color-stop(0, rgba(0,0,0,0.7)),
    color-stop(1, rgba(0,0,0,0))
  );
  test: -webkit-wht(
    test
  );
}
````

Highlight ``not``
````
@media not screen and (color), not print and (color) { }
````

serif or sans-serif and when font-family give value not null but string class
````
fieldset span button, fieldset span input[type="file"] {
  font-size:-12px;
  font-family:Arial, Helvetica, sans-serif;
}
````