plug branch delete command and lornajane and sebastianbergmann command

                    
|Q            |A   |
|---          |--- |
|Bug fix?     |y   |
|New feature? |n   |
|BC breaks?   |n   |
|Deprecations?|n   |
|Tests pass?  |y   |
|Fixed tickets|#170, #168 |
|License      |MIT |
|Doc PR       |    |