Azure storage client connexion is now separated from the Stream class, and
is located in AzureStorageClient class implementation (each instance
represents a different client, i don't see the point of having several but
whatever)
Messages Ids are now UInt64 and not Int64 anymore
The project (EvernestBack) type had been switched from library to console executable for
comfort reasons (if it breaks the build of the whole project, feel free to
switch it back and i'll avoid touching it)
Objects which used to manipulate Azure storage client's objects (like
Stream or WriteLocker) now manipulate a block blob instead (which is more
representative of a stream), there still isn't any new implemented method
though
Stream are now created by AzureStorageClient objects by passing them the
block blob they're supposed to handle

Also sorry for the long commit and for any inconvenience which may ensue
(still a n00b)
coherence with the head, i'll stick with the library type