Changes for version 0.15
- Changed hard-coded 'D' and 'T' prefixing to use _nodeify subroutine
- Added connected_components method
- Began adding support for file-based hashes using MLDBM, enabling very large collections.
- Minor bugfixes, now tests for D: and T: prefixes explicitly, instead of assuming that those are the only node types.
- Search::ContextGraph - spreading activation search engine