* Stack underflow: Add failing test to catch #31
* ensurePop, use proc instead of template + add comment for future refactoring of popInternal
* Check stack underflows before popping values
* run json tests again
* Constants and accounts compile as standalone
* Mass replace ttmath by Stint
* Adapt utils_numeric proc
* Adapt memory.nim
* Deactivate "ValidationError" test that requires pow(2, 256) function
* Fix state_db toByteArrayBE
* Fix more getUint toInt conversion
* Remove absolute value ambiguous call
* Stub-ify proc and opcode that requires pow - https://github.com/status-im/nim-stint/issues/37
* Enable vm_tests, remove usage of from keyword as a variable name
* Fix Genesis types and use the new EthTime
* Add a new VMKind enum (py-evm vmclass runtime type)
* renaming block_obj to block_types
* chain.BlockHeader and utils.header.Header are the same thing (BlockHeader in py-evm)
* For now blockNumbers are UInt256
* EoD merge: vm_test compiles and does not throw computation error
* running full transactions is too early
Todo
Pass most VM opcode tests that we can (of those that don't depend
too much on porting the whole py-evm)
Simplify a bit the current py-evm-inspired internal loop arch