Add defensive catch for HttpException

This will be thrown when called via WCF with legacy ASP.NET mode enabled
(e.g. HttpContext is available) where the InputStream is not accessible
at the point in time we normally handle the error.
Merge branch 'master' into fix-issue-65

Conflicts:
	Mindscape.Raygun4Net/Messages/RaygunRequestMessage.cs
Merge pull request #66 from MindscapeHQ/fix-issue-65

Add defensive catch for HttpException