Spike to test out DirectLeafNode implementation
Extended spike to add DirectInternalNode
Bug fix for Insert method.
Refactored to remove old node implementations.

Removed the INodeFactory and its implementations. Replaced old LeafNode
and InternalNode with DirectLeafNode and DirectInternalNode
implementations.
Commit before refactoring BinaryFilePage implementation.
Completed refactoring of BinaryFilePage

Basic store tests now all pass.
Merge branch 'feature/directnodes' into develop