facia tool: edit multiple fronts

Open in two or three panes, to edit multiple fronts. Note the ironic use of `<frameset>`.

![fronts-tool](https://cloud.githubusercontent.com/assets/1147913/4663670/b21e5f02-553d-11e4-86a8-40b9ea5fcb20.png)

![screen shot 2014-10-16 at 14 53 18 2](https://cloud.githubusercontent.com/assets/1147913/4663481/f4c90584-553b-11e4-88ac-9e08527f9ba5.png)