* begin with a block/state dag approach in prep for fork choice
* add TODOs for fork choice items, add data structure for forks
* remove syncing and processing states for incoming block sync
* simulator only broadcasts blocks now, no more state simulation
* fix sim tests, no more state sim
* bazel rerun
* naive fork choice
* split update head routine
* pesky race conditions
* fork choice rule works
* dag + fork choice working
* canonical head storage across sessions
* todo: save dag
* no more stalling after 10 blocks, using event feeds
* address review
* sync instead uses event feed
* refactored pure funcs into casper package
* tests pass
* fix lint
* refactor get blockhash
* refactor blockhashforslot
* event feed for incoming blocks in chainservice
* use config
* addressed all comments
* fix typo
* address yutaro comment
* using db interface
* check if parent hash in previous slot DAG
* works
* tests
* drop ffg suffix
* bazel gazelle
* full cov validators by height shard
* gazelle
* state tests
* all state tests
* 100% cov types and 99% cover casper
* cov up
* 80% blockchain cov
* fix lint
* Initial commit to extract initial sync code
* Add stop/resume of sync/intialsync
* bazel run
* gometalinter
* add tests
* cleanup
* build fixes
* use infof rather than errorf if sync is not in correct state
* Add TODO comment detailing eventual completion of transition from initial sync to sync
* fix build
* pr comments
* fix tests
* bump
* Adding proto topics
* Adding crystallized state request
* Reverting shanges to proto
* Adding db checks
* get crystallised state
* Finalize epoch for mapping
* more changes
* cleaning up main routine
* adding tests
* fix test
* Adding ability to save blocks
* Adding block fetcher
* Another test for setting finalized epoch
* adding final tests
* finished tests
* adding comments
* gazelle
* Making requested changes
* Fixing lint
* stop sync from exiting
* fixing lint
* lint
* Adding new request type to proto
* Making changes to block/state requests
* Change tests
* fixing error messages
* gazelle and lint
* adding back crystallised state
* fix tests
* Fixing merge conflicts
* Addressing review comments
* Changing back to one service
* removing case
