* use repeat_hash from spec in randao
* add some logging to state processing
* export crypto string converters in spec insulation layer
* enable block signature verification
* ssz: add support for arrays, remove custom data type code
* correctly handle previous and new block
* add trivial block processing tests
* prefer iterative repeat_hash
* state transition mostly done
* handle most specials and slashings
* more work on block processing
* fix some unsigned issues
* fix ssz issue when last chunk is not full
* work around empty const seq compiler bug
* XXX -> TODO