Using pointers is just plain wrong here, because the batch can be updated with
newer values for the same keys.
Fixes Seek() to use HasPrefix also because this is the intended behavior.
add close function to storage interface
add common defer function call which will close db connection
remove context as soon as it's not needed anymore
updated unit tests
* Made Encode/Decode message public.
* Added Redis storage driver and made some optimizations for the initialising the blockchain
* removed log lines in tcp_peer
* Added missing comments on exported methods.
* bumped version
