* better abstraction
* using ristretto
* begin on custom, cached array roots merkleization
* do cache initialization
* passing with new cache
* works
* fix up test
* fixed up cache
* include proper comments
* remove old hash tree root
* rem validator bottleneck
* gaz
* Merge branch 'master' into caching-ssz
* optimized!!!!
* Merge branch 'caching-ssz' of github.com:prysmaticlabs/prysm into caching-ssz
* add mutex
* Merge branch 'master' into caching-ssz
* add read lock
* fmt
* add mathutil
* Merge branch 'master' into caching-ssz
* Merge refs/heads/master into caching-ssz
* Merge refs/heads/master into caching-ssz
* Merge refs/heads/master into caching-ssz