Bug fixes (#189)

* planner fixes.
* shaper fixes.
* executor fixes.

v1.7.3 (#186)

skip/include fixes. (#178)

version bump. (#176)

Visibility controls (#173)

Restore `AlwaysVisible` (#171)

GraphQL Ruby compatibility. (#170)

GraphQL 2.4 compatibility (#166)

v1.5.1 (#159)