Add an all to the series list

Adds an all to  series opds to allow easier browsing of the series list on opds. I have attached a picture of it working.
![screenshot 2014-07-16 20 35 09](https://cloud.githubusercontent.com/assets/932691/3604452/8b7e9e76-0d20-11e4-9da2-b338d5e9608b.png)