Add error reporting for network registration
Merge pull request #55 from lpotter/errors

Add error reporting for network registration
Merge pull request #65 from monich/abi

Reduce the object sizes to avoid breaking ABI
Bump version to 0.65
[libqofono] Added QOfonoModemInterface class

It implements common patterns for QOfono classes that reprosent modem
interfaces (waiting for interface to appear in the interface list,
requesting properties etc). And it's doing it all asynchronously.