Simplified Razor Configuration API.

[ericburcham]

The interface is done, along with relevant unit tests. I'm landing the pull request now. I have to start moving to production with that ASAP in my local environment, but if you have constructive criticism, I'm happy to comply with your wishes.

In the meantime, here are the nuts and bolts of what I did.

• There is only one interface involved: IProvideReportConfiguration. It is implement by ReportConfigurationProvider.
• There is an overloaded constructor in MvcReportViewerIframe, which takes an instance of IProvideReportConfiguration.
• There is a new extension method in MvcReportViewerExtensions which takes an instance of IProvideReportConfiguration.
• As a curiosity, it would up NOT being part of the fluent API, because… what for? There is only one call… @Html.MvcReportViewer(configuration);
• Also, worth noting, I have created a MockHelpers class that allows you to mock a decent HttpContext, including the current Session… necessary for test coverage of calls to ILocalReportDataSourceProvider.Add.
• Finally, I removed the generics on the calls to ILocalReportDataSourceProvider.Add(). They were unnecessary, and don't provide any value to the caller. This let me deal with a collection of data sources in IProvideReportConfiguration.