Improve ASP.NET performance by up to 15%

On my setup, this improved the performance of the 'json' test by 15%:

1. Disable IIS HTTP logging to match the other tests. (3-5%)

2. Remove unnecessary HTTP response headers to match the other tests. (0%, but should probably be done anyway)

3. Disable support for direct access of *.cshtml and *.vbhtml files since we use MVC routing functionality instead. (13%) I identified this issue by using the [Windows Performance Toolkit](http://msdn.microsoft.com/en-us/performance/cc825801.aspx) to profile the code.

FYI: @pdonald, @micahasmith, @ollyw, @rafaelsc

P.S. This branch also includes some other fixes from my parent master branch. I didn't intend to include those changes with these performance improvements, but I couldn't find a way to back them out. In the future, to avoid this problem, I will keep my master branch clean and only put changes in branches off of my master branch (I think that makes sense).