BST: empty tree when created.
BST: Not empty when an element was added.
BST: refactoring.
BST: Remove all elements.
BST: No duplicates.
BST: Contains element.
Merge branch 'master' into bst
Merge branch 'master' into bst
BST: Test coverage improvement.
BST: Removing for leaves.
BST: Removing from root.
BST: Removing a regular node.
BST: Natural ordering test.
BST: Fixed bug with lost left nodes.
BST: Refactoring - extracted interface.
BST: Fixed bug with the clear() method.
BST: Comparable test suite.
BST: Remove method refactoring.
Merge pull request #1 from ffbit/bst

Binary Search Tree implementation