given the good feedback we got, this is take 2
of the BITAuthenticator interface.
It's simplified, cleaned up and now allows full
control over the authentication process.
Major changes:
* manual mode
Authenticator provides the bits to show the
viewController to identify the user as well as to
trigger validation on behalf of the developer.
* process separation
identification and app-usage-restriction are now
2 completely separated things.
* public identifier
Authenticator now allows the developer to query
parts of the information, e.g. the UDID or the user's
emailaddy once identified
* factor out HockeyAppClient
* configure Authenticator with HockeyAppClient
* move appendPostValue to HockeyAppClient (& add the missing boundary parameter)
* move tests over to new file
