message: Add travis build status badge icon to README
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  +[![Build Status](https://travis-ci.org/graphql/graphql-language-service.svg?branch=master)](https://travis-ci.org/graphql/graphql-language-service)
  +
  GraphQL Language Service provides an interface for building GraphQL language services for IDEs.
  Partial support for [Microsoft's Language Server Protocol](https://github.com/Microsoft/language-server-protocol) is in place, with more to come in the future.
  