- copy from legacy MVC
- get `ListBox[For]()` methods in correct places and working
- also usual stuff: `var`, `[NotNull]`, remove `IDictionary<,>` overloads
- `ListBoxHelper()` -> `GenerateListBox`
- already had all the bits needed in `GenerateSelect()`
- special-case `null` or empty `name` in GenerateSelect()
- ensure `ArgumentException` has correct parameter name
- lower-level problem affected `CheckBox()` as well
- use `ListBox()` and `ListBoxFor()` in MVC sample
- use `ListBox()` in an editor template
dougbu