Three weeks this time... the previous post...

* header.php, user/profile.php: Trying to access array on null and Undefined variable PHP warnings dirty fix for trying to access nonexistent or formerly existing user profiles
* viewuser.php: Additional checks added for nonexistent and formerly existing users... also for UID 0, which should never exist
* viewstory.php: very old $priner typo fix
* admin/blocks.php: remove original variable fix as the issue was actually at blocks/menu/menu.php
  - this also broke variables.php viewing so needed removing anyway
* browse/class.php: Uncaught TypeError in PHP 8 with visiting a classification type that has no classifications listed
  - also Undefined array key, Trying to access array offset on null, and another Uncaught TypeError [fixes]
* browse/categories.php, browse/ratings.php: Add 'no results' message for empty results
* includes/mysqli_functions.php: add set_charset to query - security-related
  - and fix a self-caused copy-paste oversight with it
* Collation change in classifications sorting/handling
* various block directories' admin.php files: formatting changes
* various block directories' init.php files: SQL engine change and consistency fixes
* includes/load-bearing.php: Fix amusing misspelling of the word variable [was spelled 'Varaible' in seven places]
* more general cleanup in various parts of the script - usually forgotten error suppression hacks someone added some time ago and odd hardcoded stuff I added in places