[WIP] Seamless layout for pictures

Refs https://github.com/owncloud/gallery/issues/5

![untitled](https://f.cloud.github.com/assets/639688/2491412/9e040be8-b1eb-11e3-9f02-c9414e1f5c28.png)

TODO list:
- [x] show icon-loading until first pictures are displayed
- [x] fix opening pictures
- [x] fix album navigation
- [x] improve performance
- [ ] fix public access

CC @owncloud/designers