towards generic method polling and reposito;y; config settings to
filterevents/methods by account address; refactoring some stuff out of
repo and into converter; remove fetcher and instead call
blockchain's FetchContractData directly; finishing tests
- Only syncs block headers (excludes block bodies, transactions, receipts, and logs)
- Modifies validation window to include the most recent block
- Isolates validation window to the variable defined in the cmd directory (blocks
have a separate variable defined in the block_repository for determining when
to set a block as final)