Support for multiple pages and other fixes

Choose page count (up to 10) from File > Paper Setup...

Pages will be added / removed as needed but image panels are not affected.

![screen shot 2014-11-10 at 23 32 20](https://cloud.githubusercontent.com/assets/900055/4985856/fff12388-6931-11e4-9662-f4720ae9f0f5.png)