It's not needed any more with Go 1.13 as we have wrapping/unwrapping in base
packages. All errors.Wrap calls are replaced with fmt.Errorf, some strings are
improved along the way.
Fixes things like:
* exported type/method/function X should have comment or be unexported
* comment on exported type/method/function X should be of the form "X ..."
(with optional leading article)
Refs. #213.
* Virtual machine for the NEO blockhain.
* fixed big.Int numeric operation pointer issue.
* added appcall
* Added README for vm package.
* removed main.go
* started VM cli (prompt) integration
* added support for printing the stack.
* moved cli to vm package
* fixed vet errors
* updated readme
* added more test for VM and fixed some edge cases.
* bumped version -> 0.37.0
