Database: Change from mysql to mysqli functions

Hello
I have had this patch laying around for some time.
Where to start.. For the most part this only changes mysql to mysqli function, but also adds a function for db connect and it removes the mres function (now replaced by dbEscape function in dbFacile.php)

This removes support for PHP < 5 and MySQL < 4.1. Hopefully no one is using that in 2015
I was thinking of doing something in OOP, but I have understood that is a bit of no-no in this project, besides that would also change a lot more code.

Have been running this in my test environment for 6+ months (PHP 5.3, MySQL 5.1)) and in my production environment for 2-3 months (PHP 5.4, MySQL 5.1) I feel confident in it's usage. However I do not use every function in Observium, so it would be cool if others could try this out.

Another reason for this is also that mysql* functions has not been recommended for years, and as of PHP 5.5 the functions has been deprecated.

As already said, hope someone can test. I also welcome suggestions