Small yet useful fix


```
1) WebDriverTest::testDoubleTap
ErrorException: Undefined property: RemoteWebDriver::$touch

vendor/facebook/webdriver/lib/remote/RemoteWebDriver.php(282)
vendor/facebook/webdriver/lib/interactions/WebDriverTouchActions.php(50)
```
Merge pull request #94 from DavertMik/patch-1

touch property not defined