v0.17.0

This release introduces lots of changes to repository structure and development
process.

• The master branch no longer tracks the vendor directory. This means that it
  is not suitable as a ProcessWire module. Instead you need to use latest release
  tags as a ProcessWire module. Release branches are a minified version of this
  module that includes everything needed and works out of the box. The master
  branch is used for development.
• Now we have a Continious Integration implemented.
  This means that people can contribute confidently by running test suite and
  be sure that nothing has broken and a pull-request will be merged.
• $ProcessGraphQL->executeGraphQL now accepts payload & variables as an
  argument. This allows you to modify the payload from client and manually pass
  it to the module to meet your needs.