datafaker --help should show commands in order and grouped nicely

[tim-band]

Datafaker help should show the commands grouped and in order so, for example

Getting source data:

• make-tables
• configure-tables
• configure-generators
• configure-missing
• make-vocab
• make-stats

Writing fake data:

• create-tables
• create-data
• dump-data

Removing fake data:

• remove-tables
• remove-vocab
• remove-data

Other utilities

• list-tables
• version