Minor Bug Fix Release.

This is a bug-fix release with a couple of minor enhancements:

1. The print_tree method can now be used on any node, not just the root node
2. The <=>' spaceship operator now checks for the correct comparison object type, and returnsnil` if invalid types are provided
3. Integration with Rspec has been started, and
4. Other minor documentation updates and bug fixes.

Release 0.9.6

This release is identical to R0.9.5, except for the fix to the Gem release date.

Release 0.9.5

This is a feature and bug-fix release.

1. Added new methods for getting the path of a node as a string. These have been added as a new mix-in as Tree::Utils::TreePathHandler. Thanks to @MZic.
2. Fixed issue #32 and enabled move semantics on the Tree::TreeNode#add method, so that a child being
   added, that has an existing parent, will be removed from its old parent, prior to being added to the new location.
3. Added performance improvements to Tree::TreeNode#is_root? and Tree::Utils::TreeMetricsHandler#node_depth. Thanks to @aidansteele.
4. Added Tree::TreeNode#rename and Tree::TreeNode#rename_child methods by merging in code from pull request #35. Thanks to @packetmonkey.
5. Fixed issue #13 with the patch provided by @jhamon.
6. Fixed a bug in Tree::TreeNode#print_tree with the patch provided by @packetmonkey.
7. Fixed issue #31, which was causing incorrect behavior in Tree::TreeNode#postordered_each and
   Tree::TreeNode#breadth_each methods when a block was not provided.

Release 0.9.2

This is a feature and bug-fix release.

The Features

• Rubytree now supports postordered traversal via the Tree::TreeNode#postordered_each` method. Thanks to Paul de Courcel for this.
• The Binary tree now supports inorder traversal via the Tree::BinaryTreeNode#inordered_each method.
• Ability to merge in another tree at a chosen node, or merge two trees to create a third tree. Thanks to Darren Oakley for this (pull #2)
• RubyTree now mixes in the Comparable module.

The Fixes

• (Partial) fix for preventing cyclic graphs in the tree
• Refactored the Tree::TreeNode#each method to prevent stack errors while navigating deep trees (issue #12)
• Check to ensure that the added node's name is unique to the destination tree (pull #9). Thanks to Youssef Rebahi-Gilbert for the idea and the initial code
• Fix for (issue #23), where the tree traversal on a binary tree would fail if the left child was nil.
• The traversal methods Tree::TreeNode#each, Tree::TreeNode#preordered_each, Tree::TreeNode#postordered_each and Tree::TreeNode#breadth_each now correctly return an Enumerator as the return value when no block is given, and return the receiver node if a block was provided. This is consistent with how the standard Ruby collections work.

Other Changes

• Structural changes in the code to refactor out the non-core functions into modules (mostly by extracting out non-core code as mixins).
• Significant refactoring of the documentation. The Yardoc tags are now extensively used.
• Basic support built-in for including example code in the Gem. This will be fully expanded in the next release.
• Various changes to the bundler, travis-ci and other Rakefile related changes.