Tooltips

Adds some missing tooltips, please check for content and spelling.

However, i had difficulties to display the starrating tooltip in the skin.xml.
Probably the widget itself does not trigger the display of tooltips because ratings works on hover.

This was the lines used in Deere for testing.

```xml
      <StarRating>
          <TooltipId>starrating</TooltipId>
          <ObjectName>StarRating</ObjectName>
          <SizePolicy>min,min</SizePolicy>
          <MinimumSize>30,30</MinimumSize>
          <Group><Variable name="group"/></Group>
      </StarRating>
```