review TouchActions to be performed and compliant with java

Java implementation here : 
* https://code.google.com/p/selenium/source/browse/java/client/src/org/openqa/selenium/interactions/touch/TouchActions.java#32

The Python implementation did an another approach, which is to just add a public method perform() to the TouchActions class : 
* https://code.google.com/p/selenium/source/browse/py/selenium/webdriver/common/touch_actions.py#24

But I prefer the Java approach because first, this is the reference and you can also play with the parent methods if you want.

Anyway, it needs a review because we can't perform actions with this actual class !