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 delete blobs or whole storage volumes
Change to the updated qabel storage branch
Rename file to blob
Tidy up after every test.
Remove slash from public identifier in StorageVolume.

Adding the slash in every StorageHTTP method
Change data variable to generic
Fixed file en/decryption test tear-down and test interdependency

Closes #221
Closes #222

Test files are now removed after testing and the decryption test is now
longer depending on a pre-running file encryption test.
Remove raw types of parameterized HTTPResult
Don't disconnect the connection in retrieve.

Otherwise is the InputStream empty.
Update class diagram
Eliminate more raw types.
Create data folder on travis server
Set the data in retrieveBlob if the result isOk.
Merge pull request #224 from k-c13/class-diagram

Update class diagram
Merge pull request #223 from cburkert/fix_tidyup_test_files

Fixed file en/decryption test tear-down and test interdependency