Support for ASP.NET syntax

Extend markup to support highlighting of ASP.NET directives (<% ... %>), and server side script tags (script runat="server"...)  containing .net code (as horrible as that is).

The hacks are there because asp.net directives inside attributes cause the css and javascript tag patterns to end the opening tag too eagerly. The markup tag regex is fine though.

One issue I see, aspnet extends markup, however it can also contain javascript and css. That's fine if aspnet is loaded _after_ javascript and css (since they'll have augmented markup), but if loaded later, those tags aren't going to render properly as aspnet. Also, aspnet can contain csharp, but it's not guaranteed this will be included at all, so server script tags won't have any highlighting.

Being able to require multiple languages (or at least mark recommendations) might solve this.