Move Enginio::isInitialized() logic to private class.
Add missing EnginioClient::Area values
Implement simple CRUD autotest for user area.
Change EnginioClient::sessionToken type to be QByteArray.

The token is used mostly as QByteArray and it is just a latin1 character
set anyway.
Implement authentication structure

EnginioIdentity classs is based class for all authentication calls,
it purpose is simple: get session token which would be used during
Enginio server communication.

EnginioAuthentication class is simple user/password authentication
method, which connects to Enginio server and query users there.

Current, approach is to login via an asynchronous call, but in future
it would be nice to have also a synchronous way to do it.
Keep session token only in two places instead of three.

Currently session token is kept in 3 places in EnginioClient as a
property, in shared QNetworkRequest and in EnginioIdentity. We can not
get rid of last two, but can kill the first one.
Simplify token handling during login operation.

We do not need a real token getter and without it, code is simpler.
Add EnginioQmlClient::isAuthenticated read-only property

The property significantly simplify EnginioModel usage when a data is
protected and a query had to be executed after authentication.
Decouple EnginioIdentity from EnginioClient.

The change allows use to use one EnginioIdentity with multiple
EnginioClient instances and it solves ownership problem.
Fix issue of having multiple Identities before clientInitialized signal.

clientInitialized signal should trigger authentication check only on
the last identity.
Merge pull request #22 from nierob/cleanupAndLogin

Basic Authentication implementation.