Update usages of $GLOBALS['TYPO3_DB']

[Chrissitopher]

For the variables these are the places to look at:

find -type f -exec grep -l "TYPO3_DB" {} \;
./piwikintegration/Classes/Tracking/Tracking.php
./piwikintegration/Classes/Hooks/BeUserProcessing.php
./piwikintegration/Classes/Lib/Div.php
./piwikintegration/Classes/Lib/Config.php
./piwikintegration/Classes/Lib/Extmgm.php
./piwikintegration/pi1/class.tx_piwikintegration_flexform.php
./piwikintegration/class.ext_update.php

See http://jans-blog.helke.de/2016/04/14/migrate-from-the-typo3-database-wrapper-to-the-doctrine-dbal-syntax/ for migration examples.