new mapping for interop api (CityOfZion/neo-storm#10)

* new mapping for interop api

* Fixed interop API mapping + added missing apis

* added engine apis

Imported from CityOfZion/neo-storm (ec5e6c8e2b587704a1e071e83b633d2d3a235300).

interop/engine/engine.go

@@ -0,0 +1,29 @@
+package engine
+
+import "github.com/CityOfZion/neo-storm/interop/transaction"
+
+// Package engine provides function signatures that can be used inside
+// smart contracts that are written in the neo-storm framework.
+
+// GetScriptContainer returns the transaction that is in the execution context.
+func GetScriptContainer() transaction.Transaction {
+	return transaction.Transaction{}
+}
+
+// GetExecutingScriptHash returns the script hash of the contract that is
+// currently being executed.
+func GetExecutingScriptHash() []byte {
+	return nil
+}
+
+// GetCallingScriptHash returns the script hash of the contract that started
+// the execution of the current script.
+func GetCallingScriptHash() []byte {
+	return nil
+}
+
+// GetEntryScriptHash returns the script hash of the contract the started the
+// execution from the start.
+func GetEntryScriptHash() []byte {
+	return nil
+}