The Hitchhiker's Guide to SQL Injection prevention

*Disclaimer: My English is far from perfect and this text has been written when it was even worse. If you can't stand such poor grammar and can afford to do a bit of proofreading, [here is the source on Github](https://github.com/colshrapnel/phpdelusions.net/blob/master/sql_injection.md), all pull requests to which will be accepted with gratitude.*