Compilation of Views should be affected by changes to _ViewStart files

that are applicable to the view.

Fixes #974
Chatted with @Praburaj and @Tratcher about the trigger. @Praburaj is going to be working on adding a file system watcher to `IFileSystem` that gets set up when you do `IFileInfo.Watch()`. `IMemoryCache` would have an adapter to the returned result which would allow us to largely remove this type.