Fix an issue which will show the AppRateBar behind the ActionBar

Create a new method to get the ActionBarHeight
--> Move this method to the Utils like your method getStatusBarHeight

With the previous attempt to get the ActionBarSize it caused some issue if the TranslucentDecorView was used.
See the screenshot on the bottom.

Now it should work in 90% of the cases. It will still cause issues if someone has a custom-rom with a different ActionBarSize.

For my private projects i use the DrawInsetsLayout but we can't use it here.


![screenshot_2014-05-25-13-22-43](https://cloud.githubusercontent.com/assets/1476232/3076883/6a1832e4-e401-11e3-871a-0eb115a6b68b.png)