4194da19c6
This helper method to return the keys for the registry will give capability to eliminate some code. Example:
```ruby
keys = []
@subcommands.each { |k,v| keys << k }
keys.sort.each { |k| o.seperator "#{k}" }
```
Versus:
```ruby
@subcommands.keys.sort.each { |k| o.seperator "#{k}" }
```