Issue #913, #1123 - Using TypeConverter in ModelBinding.

Issue #913 - Model-binding is being case-sensitive when binding Url data to Enum parameter.
Fix: Using TypeConverter solves this problem.

Issue #1123 - TypeConverterModelBinder cannot bind "byte" and "short".
Fix: Modified code to use TypeConverter which can handle these scenarios.
There's a method in there called `UnwrapNullableType` that you could use there which effectively gets you this behavior.