Remove extra indirection and directly call EnginioClientPrivate::networkManager() in the pimpl class.
Add internal EnginioClient::customRequest for low level REST API access.
Add EnginioBackendManager for tests to create / remove backends.
Merge pull request #103 from bbandix/backendManager

Backend manager
Merge pull request #104 from gladhorn/smallfixes

Smallfixes
Implement file download variants
Use thumbnails in the list
Image Gallery example C++