Use default match function

With `ac-cider-match-everything`, auto-complete doesn't filter candidates correctly.

![screenshot 2014-09-26 12 16 22](https://cloud.githubusercontent.com/assets/356330/4415484/fd8ce9d0-452b-11e4-849b-f70b0e38b5a4.png)

This screenshot describes the problem. After the first 2 characters input(`cl`), auto-complete displayed candidates and did not update candidates with subsequent inputs.

The cause is that  `ac-cider-match-everything` just returns `candidates`.
 If `match` isn't specified, auto-complete internally uses `all-completions` function for the match function, which works perfectly.