idea: add file-content middleware on the fly

[shakyShane]

Use case:

You have a an API endpoint that you're hitting and getting json back from. How cool would it be if the UI had a code-editor built in where you can modify (in real time) the json that a specific path points to.

1. Should be togglable on/off
2. Should be able to select an already-visited path from a list or auto complete thingy
3. Code highlighted editor with json validation as you type