core: refactoring blockchain state and storage

add dao which takes care about all CRUD operations on storage
remove blockchain state since everything is stored on change
remove storage operations from structs(entities)
move structs to entities package

pkg/core/interops.go

@@ -8,6 +8,7 @@ package core
 */
 
 import (
+	"github.com/CityOfZion/neo-go/pkg/core/entities"
 	"github.com/CityOfZion/neo-go/pkg/core/storage"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/vm"
@@ -18,14 +19,14 @@ type interopContext struct {
 	trigger       byte
 	block         *Block
 	tx            *transaction.Transaction
-	mem           *storage.MemCachedStore
-	notifications []NotificationEvent
+	dao           *dao
+	notifications []entities.NotificationEvent
 }
 
 func newInteropContext(trigger byte, bc Blockchainer, s storage.Store, block *Block, tx *transaction.Transaction) *interopContext {
-	mem := storage.NewMemCachedStore(s)
-	nes := make([]NotificationEvent, 0)
-	return &interopContext{bc, trigger, block, tx, mem, nes}
+	dao := &dao{store: storage.NewMemCachedStore(s)}
+	nes := make([]entities.NotificationEvent, 0)
+	return &interopContext{bc, trigger, block, tx, dao, nes}
 }
 
 // All lists are sorted, keep 'em this way, please.