Known bugs, fixed here.

mysql.php throws a diferent than "PDOException". This leads to an ugly error page when a user tries to install to a database that doesn't exist. This catches the error. We might consider trying to create the database. Reference https://github.com/anchorcms/anchor-cms/issues/638
http://www.php.net/manual/en/language.types.string.php
"When a string is specified in double quotes or with heredoc, variables are parsed within it."