MDL-18229 Grades: singleview report mega cleanup.

Fix all the things, including:
* Fix $PAGE->url
* Fix coding style.
* Add event for reportviewed
* Removed broken callback  gradereport_singleview_profilereport
* Removed vertical-align-middle
* Changed prefixes in css
* phpcs fixes
* moodlecheck fixes including phpdocs
* Move classes to use autoloading
* Remove all smelly code tricks like func_get_args, scandir etc (lots).