* Move BeaconNode type to its own file (fewer imports)
* disentangle sync protocol/request manager
* fix some old nimisms
* de-fear some logs
* simplify eth1 data production
* add stack tracing to release builds
* drop release compile flag for testnet
* spec updates
* make several constants uint64 to help minimize casting
* document data type woes - will have to revisit these
* change comment style on fields and constants to make room for better
comments
* add BLSVerify and BLSAddPbkeys facades to insulate spec code from
milagro
* fix proof of possession type
* drop explicitly ordered container fields from ssz - there's an issue
open to sort this out before committing it to the spec