rubytree version 0.6.1 has been released!

RubyTree is a Ruby implementation of the generic Tree data structure. It provides a generic tree data-structure with
ability to store keyed node-elements in the tree. This implementation is node-centric, where the individual nodes on
the tree are the primary objects and form the leafs of the structure. The implementation mixes in the Enumerable
module.

Changes:

### 0.6.1 / 2010-01-04

* Changed the hard-dependency on the 'structured_warnings' RubyGem to a soft-dependency - which lets Rubytree still
work if this RubyGem is not available. The rationale for this is that we should not require the user to install a
separate library just for one single edge-case function (in this case, to indicate a deprecated method). However, if
the library _is_ available on the user's system, then it will get used.