WL#3434: PHP: ext/mysql -> ext/mysqli converter tool -- article how to use

Write an article which describes the usage of the MySQL ext/mysql->ext/mysqli
converter tool. The article is targeted at users of the tool. 

It's planned to use an article series instead of classical documentation to
describe the tool. The advantage of articles is that we can them for marketing
purposes. Classical documentation seems not needed as the usage of the tool
itself has to be made self-explaining.