HTTP 404 already set in index.php
Revert "HTTP 404 already set in index.php"

This reverts commit 92f7e8cb511b3795a2f9f942121503c5a9ea4843.
HTTP 404 already set in index.php
Improved database connection validation

Checking if any data installed
"Drop table if exists" as an option

Removed unused $optional_title
$results moved from install.php

Removed unused $optional_title