Add transaction logs into block info

This feature will enable fetching transaction logs in batch with block info

v0.4.3

add a field into AccountMeta to describe if account is a contract.

v0.4.2

update github.com/grpc-ecosystem/grpc-gateway (#93)

v0.4.1: mock iotexapi (#91)

* mock iotexapi

* integrate make cmd

1. move mock files to golang/iotexapi/
2. integrate make cmd and update README.md

upgrade protobuf to 1.4.2

v0.4.0

upgrade (#90)

v0.3.2

read state: buckets count (#88)

finish native staking api

v0.3.0

change to get buckets by indexes (#68)

add native election api

v0.2.5

add election api (#43)

v0.2.0

1. Add RESTful ==> gRPC reverse proxy server using Google's grpc-gateway package
2. Add field 'Total' into GetActionsResponse and GetBlockMetasResponse message
3. Add field 'BlkHeight' and 'Sender' into ActionInfo message

v0.1.0

Initial release of iotex-proto