signed commit
Refactor logic to accomodate bufonly option
Delete the scratch buffer

Deleting the scratch buffer prints out the number of deleted buffers
when the last buffer is not scratch. If we avoid deleting the scratch
buffer, then we would never get the number of deleted buffers after the
first time Bdall is called.
Rename Bdall to BdAll
Add command to delete other buffers
Add feature to retain buffers with matching pattern
Add feature to delete buffers with matching pattern