This version simply prints out the logged in username,
for consistency.
It no longer prints out the current team name.
Squashed commit of the following:
commit 1d4ef6af9507a1180fd9e84b7cc64c7fe3e815fa
Author: Nathan Rajlich <nathan@tootallnate.net>
Date: Fri May 26 14:40:00 2017 -0700
add "whoami" to valid command names
commit 6ea37e49eb1ea2d9b5b12befe26a6a15972e1f6c
Author: Nathan Rajlich <nathan@tootallnate.net>
Date: Fri May 26 14:37:56 2017 -0700
don't log current team name in `now whoami`
Instead, consistently return the logged in username.
Not logged in:
```
$ now whoami
> Not currently logged in! Please run `now --login`.
```
Logged in, stdout is a TTY:
```
$ now whoami
> tootallnate
$ now switch zeit
$ now whoami
> zeit
```
Stdout is NOT a TTY:
```
$ echo "Logged in to Now as $(now whoami)"
Logged in to Now as tootallnate
```
Closes#585.