core, core/vm: added structure logging

This also reduces the time required spend in the VM

core/vm/virtual_machine.go

@@ -3,6 +3,4 @@ package vm
 type VirtualMachine interface {
 	Env() Environment
 	Run(context *Context, data []byte) ([]byte, error)
-	Printf(string, ...interface{}) VirtualMachine
-	Endl() VirtualMachine
 }