Issue on macOS

[Sharcoux]

I get Error: spawn rec ENOENT

The issue is located at lib/mic.js line 54.

The main issue here is that the crash is hard to catch and detect from the user application. The library should catch the error and communicate about what is going on and how to fix it. For instance:

* Install sox for audio recording :
  https://github.com/JoFrhwld/FAVE/wiki/SoX-on-OS-X