Support current version of dcd, and a little bug fix

* Update to follow current DCD.  
`ac-dcd-adjust-cursor-on-completion` is called on completion if the dcd is newer than 4.0. It will make the completion work on this version.

* Bug fix: multiple ac-dcd-flags was not accepted. 
If more than one ac-dcd-flags were set, they were unescaped and regarded as one flag. Now it's fixed.
Yes. With the former implementation, when there is multiple kind of candidates, the calltip expansion doesn't work.
Can you try to complete `scanf`? The candidate type will be "fl", and as it is not exact "f", expansion wouldn't triggered.
Using string-match instead of equal solves it.