[isf-wifidog] MySQL support

[Proulx François]

I've spent about an hour and half converting the base schema... I  
managed to convert more than 95% or the basic table definitions. I  
would still have to figure out the indexes and some special keys....  
( there are still around 100 SQL queries to fix ).  I'm only talking  
about the creation schema. I doubt MySQL even supports foreign keys.  
MySQL support is certainly possible, but at what cost, and it would  
be a pain to keep it updated. I won't do it. If someone needs it I  
can send him the file I used to generate the tables... But I'd say  
it's not worth it.