Update ElmahInterceptingLogger.cs

This now takes in an HttpApplication and uses ErrorSignal.Raise(...) to signal Elmah to log rather than tunneling directly to the error log.  This allows Elmah modules such as ErrorMail and ErrorPost (ElmahR) to push errors that are handled inside of errors within services.
Update ElmahLogFactory.cs

Update to pass in HttpApplication so the ElmahInterceptingLogger can use ErrorSignal.Get(application).Raise(<exception>).  This allows modules such as ErrorMail and ErrorPost (ElmahR) to function when using ILog.Error() or ILog.Fatal()
Update ElmahInterceptingLogger.cs

Added missing namespace
Merge pull request #888 from svantreeck/patch-1

Patch 1