Do not exit with error if current directory is the only match

Created by: jsliang

Trying to resolve issue #182 (closed). If the current directory is the only match (as @blueyed described), add the path of the current directory to results so that autojump does not exit with error.

(In current behavior, the current directory is not shown in results at all even if there is a match. This is to prevent from jumping into the current directory.)