Implements nested interval tree model using Moebius encoded continued fractions.

Based closely on http://arxiv.org/abs/cs.DB/0402051 with a few modifications.

The MoebiusInterval internal class is (I believe) fully implemented, meaning
all the algorithms for handling the tree are worked out and implemented in the
abstract.

Probable next step will be to write the Rails wrapper to make this work with 
ActiveRecord objects.