Bind events in Channel

Two new methods
- bind
- unbind

Integrated with ThunderPush welingtonsampaio/thunderpush@8568ea7

#### Send message ( POST )
**URI:** /api/1.0.0/events/event-name/
**BODY:**
```json
{
  "channel": "channel-name",
  "foo": "bar"
}
```
or 
```json
{
  "channel": ["first-channel", "second-channel"],
  "foo": "bar"
}
```

#### Javascript binds

```js
Thunder.subscribe('chat', function(channel){
  channel.bind('message:received', function(data, channel, event){
    console.log('Data:', data);
    console.log('Channel:', channel);
    console.log('Event name:', event);
    console.log('---------------------------------------------');
  });
});

```