* Recreating some of the speculative-execution code.
Not really using it yet. Also there's some new inefficiency in
memory.nim, but it's fixable - just haven't gotten around to it yet.
The big thing introduced here is the idea of "cells" for stack,
memory, and storage values. A cell is basically just a Future (though
there's also the option of making it an Identity - just a simple
distinct wrapper around a value - if you want to turn off the
asynchrony).
* Bumped nim-eth.
* Cleaned up a few comments.
* Bumped nim-secp256k1.
* Oops.
* Fixing a few compiler errors that show up with EVMC enabled.
t8n: a silly bug contract address generator, should use original
tx nonce instead of read the nonce from sender address in state db.
Although in EVM contract address generated by reading nonce from state db
is correct, outside EVM that nonce value might have been modified,
thus generating incorrect contract address.
accounts cache: when clearing account storage, the originalValue
cache is not cleared, only the storageRoot set to empty storage root,
this will cause getStorage and getCommitedStorage return wrong value
if the originalValue cache contains old value.
* Reduce Nim 1.6 compiler warnings/hints for Fluffy and Nimbus proxy
Mostly raises Defect removals, TaintedString removal and some
unnecessary imports.
Also updating the copyright years alongside.
* Further reduce Nim 1.6 compiler warnings/hints for Nimbus