Adds 'active' property to WLXConnectionManager.

The connection manager is active if it is connecting or is already
connected with a device.
Exposes the dispatch queue of the WLXBluetoothDeviceManager.
Checks if an active connection manager is already registered.

When a connection manager is registered to the
WLXCentralManagerDelegate, it first checks that there is no
active connection manger registered.
Adds 'reconnecting' property to WLXConnectionManager.
Triggers a notification when reconnecting.
Fixes typos in log messages.
Includes WLXDeviceDiscoveryData.h in WLXDeviceDiscoverer.h
Adds bluetoothOn to initializer in WLXBluetoothConnectionManager.

This allows proper initialization of this property using the state
exposed by WLXCentralManagerDelegate.
Adds the error object that cause the connection lost.

When a notification is published after failing to reconnect with
device due to an error, the error object is added to the notification.
Fixes typos in log messages.
Fixes several bugs related with the connection.
Adds WLXManagedDelayedExecutor class

This class abstracts the logic of dispatching a block to excuted
after a certain amount of time and also add the posibility to
"invalidate" the given executed once the timer has expired.
Uses WLXManagedDelayedExecutor in WLXBluetoothDeviceDiscoverer.
Exposes bluetoothOn property on ConnectionManager and DeviceManager.
Fixes bug serializing connection record.
Adds a WLXConnectionManagerDelegate

This delegates can be used instead of notification to handle
the connection state change.
Adds a WLXDeviceDiscovererDelegate.
Add test case delegate methods invocations.
Adds Example add that uses this pod.