'lexik\Bundle\TranslationBundle\LexikTranslationBundle' not found

It solves by changing from 4.0 version to 2.0 by the string in "composer.json":

"lexik/translation-bundle": "~2.0"

IDEA/phpstorm & GIT unversioned files not available

Make "cd" to needed directory and execute "git add -f <filename>, after that your IDE will see that file. Actual for image files, because it cannot modify inside Idea/Phpstorm.

How to solve PDOException “could not find driver” in Ubuntu

sudo apt-get install php5-mysql

It can answer that will be conflicts with some packages, and need to remove it, but suddenly that conflict was solved by it own. After "php5-fpm -m" command you should get pdo_mysql.