v1.5.0

Features

• BatchRequest: Add support for apollo server batch format (7d2e6223)
  It allows to 3rd party server implementations, like graphene-django be compatible with appolo client (details).

Build

• Remove babel-runtime, migrate to babel-preset-env, refreshed package.json (ab6e8df8)
• Test with travis, auto package publishing with semantic-release (6eb36166)