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.
I think you might not need to do this - we already unwrap nullable types at the start of this method