message: [json-rpc] Expose AccountAddress and SignedTransaction
  Currently code using libra-json-rpc-client needs to also import libra-types to
  use the whole interface. This exposes the other two types that are needed so a
  direct dep on libra-types in no longer needed.
  Closes:
  Approved by: thefallentree
diff: @@ -10,4 +10,5 @@ pub use client::{
  get_response_from_batch, process_batch_response, JsonRpcAsyncClient, JsonRpcBatch,
  };
  pub use libra_json_rpc_types::{errors, views};
  +pub use libra_types::{account_address::AccountAddress, transaction::SignedTransaction};
  pub use response::{JsonRpcResponse, ResponseAsView};
  