Fixes#3986
This pull request is prefixing all the types in proto to avoid conflict.
When a go application is using Tendermint as a library and also define similar types in gogo proto some conflicts might occur (as types is a common package in go).
By prefixing the types with tendermint, this highly reduces the risk of conflicts.
BREAKING CHANGE.
This modification breaks the ABCI Application endpoint.
What was accessible before with `/types.ABCIApplication/Flush` is now accessible with `/tendermint.abci.types.ABCIApplication/Flush`.
* remove gogoproto from tools
because it's not a binary
* update protobuf version to 3.6.1 in `make get_protoc`
* update libs/common/types.pb.go and rpc/grpc/types.pb.go
* fix app tests