Add comments on public classes and methods

[megahomyak]

Platform.Collections.Methods/Trees

• RecursionlessSizeBalancedTreeMethods
• SizeBalancedTreeMethods
• SizedAndThreadedAVLBalancedTreeMethods
• SizedBinaryTreeMethodsBase

Platform.Collections.Methods

• GenericCollectionMethodsBase

Platform.Collections.Methods/Lists

• CircularDoublyLinkedListMethods
• DoublyLinkedListMethodsBase
• OpenDoublyLinkedListMethods