Add the backups list method.
Add the backups API endpoints for list.
Add the API client methods for list.
Add the backups list subcommand.
Fix gocheck imports.
Adjust to baseSuite.
Return an error for a failed type assertion.
Add a missing doc comment.
Fix a typo.
Improve an error message.
Fix a type in an error message.
Add a missing return arg.
Merge pull request #835 from ericsnowcurrently/backups-list

Add the backups list functionality.