Updated ckit/brew command usage to reflect current behavior

Previously:
```
ckit --tag
```

Would default to:
```
ckit brew --tag
```

Now one must explicitly say
```
ckit brew --tag
```
Or can use the shortcut:
```
ckit b --tag
```
------
Running:
```
ckit
```
Since v0.1.0, has defaulted to:
```
ckit help
```