Filemanager: Added "first" and "last" page functionality

I am not sure how to upload the new icons since I seem not to be able to create new icons anywhere, but here they are, they need to be copied into resources/icons:

appbar.chevron.last.png:
![appbar chevron last](https://cloud.githubusercontent.com/assets/7792441/3745999/51aa45aa-17b7-11e4-8fc0-09ae578fd00e.png)

appbar.chevron.first.png:
![appbar chevron first](https://cloud.githubusercontent.com/assets/7792441/3746001/543ad5e6-17b7-11e4-9d43-826a5e0f8d52.png)