Improve Linkwizard, make it can be used more than once.

As reported in https://forum.dokuwiki.org/thread/9988
the previous implementation can not handle the situation of use the
linkwiz more than once. Now you can use in you toolbar plugin
    'type' => 'linkwiz'
to make use of the handy Linkwizard for choosing the wiki pages.
Merge pull request #235 from haobug/master

Improve Linkwizard, make it can be used more than once
fixed old pagetools sprite loading from cache when hovering
for negative or zero number of revs to return return empty array by getRevisions
Merge remote-tracking branch 'origin/master' into changelogtestsonly