Support different types of controls with Input.Model

[robdmoore]

e.g. checkboxes, radio lists, etc.

See initial work here:

• https://github.com/MRCollective/ChameleonForms/blob/master/ChameleonForms.AcceptanceTests/ModelBinding/Pages/ChameleonFormsPage.cs#L16
• https://github.com/MRCollective/ChameleonForms/blob/master/ChameleonForms.AcceptanceTests/ModelBinding/Pages/ChameleonFormsPage.cs#L29
• https://github.com/MRCollective/ChameleonForms/blob/master/ChameleonForms.AcceptanceTests/ModelBinding/Pages/ModelFieldType.cs
• https://github.com/MRCollective/ChameleonForms/blob/master/ChameleonForms.AcceptanceTests/ModelBinding/Pages/ModelFieldValue.cs
• https://github.com/MRCollective/ChameleonForms/tree/master/ChameleonForms.AcceptanceTests/ModelBinding/Pages