Added Device::isReady which checks if it has been created

This is a little bit hackish but untul 2.0 we can't do anything better.
Basically we are checking if the device has been created in the bus and
use that to decide if it is "ready" or not.

this is the only way we have to know if a device actually works.
Check if we get valid information from OrgBluezDeviceInterface
Added missing emit defaultChanged

BUG:314356
tabs per spaces and indentation fix
Properly clean the object when the service is unregistered

CCBUG:314356
Emit defaultAdapterChanged and usableAdapterChanged on initialize

After all this is the first time they change, from 0 to *

CCBUG:314356
Set m_bluezServiceRunning first thing once unregistered is called

If any user of the library connects to a signal emitted in clean
like *adapterChanged and performs any operation it will fail with
a potential crash given that the service won't be available but the
library will not know that.
emit usableAdapterChanged ALWAYS on initialize
Bump version and soname to 2.0
Update DBus interfaces for Bluez 5
Remove default adapter methods.
Port to Bluez 5

* use DBus ObjectManager to get Adapter/Devices
* remove cached properties, directly use DBus properties
* add unpairedDeviceFound signal to Adapter
* move [un]registerAgent to Manager
Register dbus metatypes in constructor
Change adapters list to QMap to get deterministic order.