iOS logs for simulator and real device

#### Setting up new features
```sh
./reset.sh --ios --verbose
```

######  Supported log types : logcat, ios
```python
self.driver.log_types
```

######  iOS logs for simulator and devices

```python
self.driver.get_log("syslog")
```
TODO: "crashlog"
<br/>
#### Fixed server crash on ADB.prototype.getDevicesWithRetry
```log 
error: uncaughtException: Cannot call method 'restartAdb' of undefined
```
#### Fixed an issue in grunt configuration
```log 
maxBuffer increased to 2000*1024 due to problems with "maxBuffer exceeded" for selendroid building 
```