zoom stick on last

```
Have the zoom stay at last level used. 
Zoom entire track button? Maybe use the compass for that?  
Thanks for the app.

What do you consider a good addition to the application.

1. Describe the function
2. Give an example on how this could fit with the current usage
3. ...

```

Original issue reported on code.google.com by `Stu.Enge...@gmail.com` on 31 Oct 2014 at 11:33
