Makes bindings more flexible by allowing developers to override converters for while still supporting implicit conversions

- Made IBindingTypeConverter usable standalone (without registration with the DepdencyResolver) by outsourcing GetAffinityForObjects into derived interface IImplicitBindingTypeConverter
- Extended Bind, BindTo and OneWayBind to take an optional parameter that allows the developer to pass in an ad-hoc IBindingTypeConverter which overrides any otherwise implicitly selected converter
- Minor improvement to Logging Output generated by PropertyBinding
- Made sure that MonoTouch Linker.xml preserves the full type for UIKit Controls and not just properties.
- Tightened WrappingFullLogger code contract