BackendManager: Cache backend environments to avoid unnecessary requests
Rename internal helper functions to match server terminology.
Fix camel case in EnginioClient: setserviceUrl -> setServiceUrl
Add a bit of docs.
Remove buggy and unused forward declarations
Merge pull request #122 from nierob/smallFixups

Remove buggy and unused forward declarations
Add backend manager function to query backend environments
and combine it with the local environments cache.
Add backend manager function to get backend API keys
e.g. {"backendId" : "ID", "backendSecret" : "SECRET"}
Fix potential memory leak in EnginioModel
Merge pull request #124 from gladhorn/imagegallery

Improve image-gallery example.
Make the search test use it's own backend.
This is the first step of a migration to per-testcase backends.
Merge pull request #125 from nierob/smallFixups

Fix potential memory leak in EnginioModel
Merge pull request #126 from bbandix/backendManager

Backend manager improvements
Merge pull request #121 from nierob/docs

Add a bit of docs.
Implement file download variants
Use thumbnails in the list

sec
Image Gallery example C++
Improve image-gallery example even more

Get the images from the right url, use
variants so that we have thumbnails in the list,
big images in detail view.