Create TestStack.Seleno.Mvc

[robdmoore]

• Pull out MVC specific things like the route registration and controller expression overloads
• Remove MVC dlls from core project
• TestStack.Seleno.Mvc4 with a dependency on MVC4 package
• TestStack.Seleno.Mvc5 with a dependency on MVC5 package

[aaronpowell]

Making good progress on this are you @robdmoore 😛

It's really quite annoying that you need to reference the MVC NuGet packages in Seleno when you're not using MVC (I'm using Seleno to automate a SPA that has no MVC at all).

[robdmoore]

:P agreed.

I actually have a WIP branch on my computer with 50% of it done