Add test cases for trying to convert valid and invalid GUID values.

Catch exception in TryConvertTo

Catch when the converter throws an exception and return false and set the out value to default.

Change to Guid specific Converter

Remove try/catch added in TryConvertTo  and replace with Guid Converter

Add case for Nullable Guid

Add tests for NullableGuid

Fix NullableGuid parse reflect a null as parsed