Update example code in README
Merge branch 'master' of github.com:moneydesktop/rubiks

* 'master' of github.com:moneydesktop/rubiks:
Nodes deep_dup the input hash in .new_from_hash
Move examples to spec folder
Require annotated_node in calculated_member
Prepare for 0.0.6 release

Closes #3
Merge pull request #4 from moneydesktop/deep_dup

0.0.6 release