Fix/cls compliance

Default parameters were causing VB to fail on compile due to ambiguous method signature.

This will be a breaking change for anyone who has passed parameters by name.

[CA1026: Default parameters should not be used](http://msdn.microsoft.com/en-us/library/ms182135.aspx)

![raven-error](https://f.cloud.github.com/assets/245305/1236130/3ada2540-29b8-11e3-9cab-80c643981c01.png)

Using

    raven.CaptureException(ex, Nothing, Nothing)

still threw the error.