restructured eth rpc API

rpc/api/api.go

@@ -0,0 +1,12 @@
+package api
+
+import "github.com/ethereum/go-ethereum/rpc/shared"
+
+// Ethereum RPC API interface
+type EthereumApi interface {
+	// Execute the given request and returns the response or an error
+	Execute(*shared.Request) (interface{}, error)
+
+	// List of supported RCP methods this API provides
+	Methods() []string
+}