Update travis.yml for storage testing
Adding StorageHTTP and StorageHTTPTest classes
Add new method to create new Qabel Storage Volumes

Add also a HTTPResult class, which contains the response code and a boolean,
if the request was successful.
Add a method, which tests the new function.
Add the probe method and the corresponding tests
Add upload method for blobs to the QSV
Add method to retrieve blobs from the QSV
Add method to delete blobs or whole storage volumes