DateTimeToString setting

T4TS is a nice little helper but you have a work around for the DateTime data type implemented by default. Wouldn't it be nice if this behavior is optional?

In my current project I am using Json serializer different than the the MVC one and the DateTime is serialized and accepted by TypeScript as a "Date" data type. My suggestion with this pull request is to translate the DateTime to string only in case it is explicitly configured in the T4TS.tt.settings.t4 to do so.