Add l2cap reconnection support on script part. Only Linux native part imlemented

Bluetooth connection can easily be dropped. In order to support automatic reconnection :
* on linux native part : allow l2cap reconnection - default number of attempts = 5
* on script part : add 'reconnect' 'connectionDrop' events to define a reconnection policy, for an example refer to https://github.com/Lahorde/node-sensortag

TODO other platform native implementation