Update block collection documentation.
Remove Traits class usage in b_tree.
Fix attribute naming in b_tree_leaf.
Fix attribute naming in b_tree.h
Fix attribute naming in b_tree_builder.
Fix attribute naming in b_tree_block.
Fix attribute naming in key_less_than class.
Fix attribute naming in key_less.
Add empty_augment and empty_augmentor classes.
Add Augment and Augmentor template parameters to b_tree related classes.
Add template parameter for empty augmentor.
Refactor unnecessary else statement in b_tree.
Add augmentation to b_tree.
Add unit-test stub for augmented B trees.
Remove traits template parameter usage in test/b_tree.cpp.