wikichecks - additional check & cleaned-up

* added param '' where lang key 'gwtoolset-permission-not-given' is used without a param
* added checkMediaWikiVersion()
* moved self::checkMediaUploadSettings() to the bottom of pageIsReadyForThisUser()
* removed @return {void} comments
* renamed verifyPHPVersion to checkPHPVersion

Change-Id: I5a69e638073393d7142bfce2d10bb14a5a2594e6
Merge branch 'master' of github.com:dan-nl/GWToolset