Fix documentation issues
Fix documentation issues

* `-prefix` was missing from many examples
* bash doesn't pass along termination signals to its children, so
  the watch-and-reload example using the shell didn't work.  Use
  an inline Python script to demonstrate it instead.

bounceexchange/envconsul,kalistace/envconsul,bounceexchange/envconsul,x-cray/envconsul,hashicorp/envconsul,x-cray/envconsul,kalistace/envconsul,hashicorp/envconsul