Implement default comparer

We should consider implementing own default comparers for certain types that make more sense than those from Generics.Defaults.

For example the comparer for string actually does a binary compare instead of string comparer (this is fixed when using TStringComparer from Spring.Collections).

As another example when having TPair<TKey,TValue> it also uses BinaryCompare / CompareMem instead of comparing TKey or TValue by default.