Config tool: validate CAPI query during entry

![fronts-tool-1](https://cloud.githubusercontent.com/assets/1147913/2781252/c7207e14-cb11-11e3-8a72-5e7427ff5780.png)

![fronts-tool-2](https://cloud.githubusercontent.com/assets/1147913/2781183/03284578-cb11-11e3-9496-0983d9f42baf.png)