Accelerometer class

1. Constructors
2. Accelerometer
3. Properties
4. x
5. y
6. z
7. activated
8. hashCode
9. hasReading
10. on
11. onError
12. runtimeType
13. timestamp
14. Methods
15. addEventListener
16. dispatchEvent
17. noSuchMethod
18. removeEventListener
19. start
20. stop
21. toString
22. Operators
23. operator ==