Cache and user photo fix

[seanjermey]

Add caching option to craftql response.

Add 'useCache' => true to config/craftql.php

To use this branch add a new repository to composer.json

"repositories": [
    {
      "type": "vcs",
      "url": "https://github.com/seanjermey/craftql"
    },`
]

... and update the version to "markhuot/craftql": "dev-cache-and-user-photo-fix",

EDIT

merged in user photo fix by Tam - #285