Improve bash-wcomp, using printf and quote_readline (gh-4)
Improve bash-wcomp, using printf and quote_readline (gh-4)

As @soli points out in gh-4, adding quotes can result in only the
opening one if bash decides to use the longest common match. This commit
utilizes bash_completion function `quote_readline' if available and
`printf' if not.

alphapapa/fasd,Neki/fasd,Vifon/fasd,allcatsarebeautiful/fasd,clvv/fasd,dankilman/fasd