Unify means of specifying environment to --env=<environment>

*If omitted & param is optional, defaults to 'dev'
*Supports arbitrary environment --env=foobar
*Deprecates support for `fhc restart appId live` or `fhc restart appId --live` - still supported but prints a warning

There'll be more work for FHC when things with dev/live specific endpoints (hosts `developmentHost`, env's `devValue`) are updated - deemed not in scope here. 
would be better to have a  ```for j in (fhc environements) ``` instead of the hard coded dev and live... but will need the fhc environments command first...

e.g.

```
$ for i in $(fhc apps --bare);do for j in $(fhc environments --bare); do echo "pinging: $i in environment $j"; fhc ping $i --env=$j; done; done
```