[Development] Dynamic QtServiceFramework backend.

[Corentin Jabot]

I made the change here https://codereview.qt-project.org/#change,25091

As suggested, I simplified the enum like that.

enum QService::InterProcessMethod {
          Native,
          LocalSocket,
}

The only thinks that changes are 2 new constructors

QServiceManager(QService::Scope scope, QService::InterProcessMethod
ipcMethod, QObject *parent = 0);
QRemoteServiceRegister(QService::InterProcessMethod ipcMethod,
QObject* parent = 0);

Due to the implementation of QRemoteServiceRegister, it is not
possible to use a setter, so I use the same construct for both
classes.
It makes more sens anyway, since we can not change the value once the
service is initialized.
In order to work, the service and the client must use the same value.

The default value is "Native", ie QDBus on where it's available and
LocalSocket everywhere else.
If a wrong value is given, it fallback on local socket - but perhaps
the other way around would have made more sens

The change should be both binary and source compatible.

Also, as it my first contribution to Qt I'm not so sure about the naming rules


Corentin Jabot.