HTML highlighting doesn't properly render for some CSS

[bobbylight]

Description
The example CSS below is not highlighted properly.

Steps to Reproduce
Paste the following into RSyntaxTextAreaDemoApp when viewing HTML:

a[foo*="bar"] { display: none } /* this is fine */
@media screen {
  a[foo*="bar"] { display: none } /* The string is unterminated here */
}

The issue is that HtmlTokenMaker kind of "cheats" with nested curly braces and doesn't render this "nested" content properly. Since CSS nesting is now standarized and available in all modern browsers, this is probably best fixed by copying functionality from the SaasTokenMaker or LessTokenMaker into the HTML, CSS, JSP and PHPTokenMakers, since they'll all have this issue.