Removed self-ban ability

See
http://beta.woltlab.com/index.php/Thread/2251-Admistrator-kann-sich-selbst-sperren-gewollt/
Fixed inconsistent usage of elseif
Merge pull request #1383 from SoftCreatR/SelfBanFix

Remove self-ban ability
Merge pull request #1384 from SoftCreatR/ConsistentElseIf

Fix inconsistent usage of elseif
Fixed undefined constant
Added support for button creation for BBCodes
Fixed check for optional element
Fixed bbcode pip