Automatically restart A::D::Query on code change

**Which issues (if any) does this change solve? (please link them here)**
https://github.com/duckduckgo/p5-app-duckpan/issues/52

**Briefly describe your fix. Are there any important details we should know about?**
Automatically restart A::D::Query when it detects a change in the instant answer file hierarchy.  Reloading instant answers via subprocesses after the application was created proved utterly intractable. 

**Are you having any problems? Do you need our help with anything?**

Forking inside...beware.